diff --git a/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStageVocabulary.swift b/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStageVocabulary.swift
new file mode 100644
index 0000000000..53fe93d28b
--- /dev/null
+++ b/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStageVocabulary.swift
@@ -0,0 +1,30 @@
+/// Which stage strings mean "awake" in a stored hypnogram.
+///
+/// The tree carries TWO stage vocabularies, and that is deliberate rather than sloppy:
+///
+/// - **Segment `stage` strings** (`StageSegment.stage`, hypnogram rows) canonicalise to `"wake"`.
+///   `SleepStagerV2` models its own states as `"awake"` internally and renames to `"wake"` on the way
+///   out for exactly this reason.
+/// - **Minutes-dictionary keys** (`SleepStageTotals`, `SleepWindowReclip`) canonicalise to `"awake"`.
+///
+/// The bug this exists to close is the dictionary vocabulary reaching a SEGMENT comparison. Imports do
+/// not pass through `SleepStagerV2`: Oura's phase table is `["deep","light","rem","awake"]`, and generic
+/// wearable JSON carries whatever the source app wrote. A consumer written `stage == "wake"` then
+/// silently misfiles those segments, and — worse — `stage != "wake"` counts them as SLEEP.
+///
+/// Six sites already defended with `case "wake", "awake"` while five did not, which is what makes this
+/// a missing shared rule rather than a missing idea.
+///
+/// A PREDICATE, deliberately, not a canonicaliser: it fixes the comparisons without rewriting any
+/// stored string, so no persisted hypnogram changes meaning and neither vocabulary above moves.
+public enum SleepStageVocabulary {
+
+    /// True for either spelling of the wake stage, ignoring case and surrounding whitespace.
+    ///
+    /// Use on a SEGMENT stage string. Minutes dictionaries are keyed `"awake"` by construction and do
+    /// not need it.
+    public static func isWake(_ stage: String) -> Bool {
+        let s = stage.trimmingCharacters(in: .whitespaces).lowercased()
+        return s == "wake" || s == "awake"
+    }
+}
diff --git a/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStager.swift b/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStager.swift
index bf74efc971..c04fe68d02 100644
--- a/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStager.swift
+++ b/Packages/StrandAnalytics/Sources/StrandAnalytics/SleepStager.swift
@@ -1072,7 +1072,7 @@ public enum SleepStager {
     static func efficiency(start: Int, end: Int, stages: [StageSegment]) -> Double {
         let inBed = Double(end - start)
         if inBed <= 0 { return 0 }
-        let wake = stages.filter { $0.stage == "wake" }.reduce(0.0) { $0 + Double($1.end - $1.start) }
+        let wake = stages.filter { SleepStageVocabulary.isWake($0.stage) }.reduce(0.0) { $0 + Double($1.end - $1.start) }
         let asleep = max(0.0, inBed - wake)
         return min(1.0, asleep / inBed)
     }
@@ -2190,7 +2190,7 @@ public enum SleepStager {
 
         var waso = 0.0
         var disturbances = 0
-        for s in segs where s.stage == "wake" {
+        for s in segs where SleepStageVocabulary.isWake(s.stage) {
             let w0 = max(Double(s.start), onset)
             let w1 = min(Double(s.end), sptEnd)
             if w1 > w0 { waso += (w1 - w0); disturbances += 1 }
diff --git a/Packages/StrandAnalytics/Sources/StrandAnalytics/WakeMotionRefinement.swift b/Packages/StrandAnalytics/Sources/StrandAnalytics/WakeMotionRefinement.swift
index 266a085183..d8703124b0 100644
--- a/Packages/StrandAnalytics/Sources/StrandAnalytics/WakeMotionRefinement.swift
+++ b/Packages/StrandAnalytics/Sources/StrandAnalytics/WakeMotionRefinement.swift
@@ -185,7 +185,7 @@ public enum WakeMotionRefinement {
     /// this pass only ever acts when BOTH read "hot-but-still".
     static func refineSegment(_ seg: StageSegment, gravByMinute: [Int: [GravitySample]],
                               ticksByMinute: [Int: Int]) -> [StageSegment] {
-        guard seg.stage == "wake", seg.end - seg.start >= minWakeSegmentSeconds else { return [seg] }
+        guard SleepStageVocabulary.isWake(seg.stage), seg.end - seg.start >= minWakeSegmentSeconds else { return [seg] }
         let mins = minutes(from: seg.start, to: seg.end)
         guard !mins.isEmpty else { return [seg] }
 
diff --git a/Packages/StrandAnalytics/Tests/StrandAnalyticsTests/SleepStageVocabularyTests.swift b/Packages/StrandAnalytics/Tests/StrandAnalyticsTests/SleepStageVocabularyTests.swift
new file mode 100644
index 0000000000..32da39a990
--- /dev/null
+++ b/Packages/StrandAnalytics/Tests/StrandAnalyticsTests/SleepStageVocabularyTests.swift
@@ -0,0 +1,80 @@
+import XCTest
+@testable import StrandAnalytics
+
+/// #979 — both spellings of the wake stage occur in stored hypnograms, and five segment comparisons
+/// only recognised one of them.
+///
+/// The damaging shape is `stage != "wake"`, used to mean "asleep": an imported `"awake"` segment fell
+/// through it and was counted as SLEEP, inflating the efficiency figure. The mirror shape,
+/// `stage == "wake"`, under-counted wake time and made the #987 wake refinement skip those segments.
+///
+/// Twin of the Kotlin `SleepStageVocabularyTest`; same cases in the same order.
+final class SleepStageVocabularyTests: XCTestCase {
+
+    /// Both spellings are wake. This is the whole point.
+    func testBothSpellingsAreWake() {
+        XCTAssertTrue(SleepStageVocabulary.isWake("wake"))
+        XCTAssertTrue(SleepStageVocabulary.isWake("awake"))
+    }
+
+    /// Sleep stages are not wake — the predicate must not swallow the rest of the vocabulary.
+    func testSleepStagesAreNotWake() {
+        for s in ["deep", "light", "rem"] {
+            XCTAssertFalse(SleepStageVocabulary.isWake(s), "\(s) must not read as wake")
+        }
+    }
+
+    /// Imported JSON is not guaranteed tidy; casing and padding must not decide a sleep score.
+    func testCasingAndWhitespaceAreFolded() {
+        XCTAssertTrue(SleepStageVocabulary.isWake("Awake"))
+        XCTAssertTrue(SleepStageVocabulary.isWake("  WAKE "))
+        XCTAssertTrue(SleepStageVocabulary.isWake("\tAwAkE"))
+    }
+
+    /// An absent or unknown stage is NOT wake, which preserves the existing behaviour of the callers
+    /// that treat "anything that is not wake" as asleep. Widening that would be a separate change.
+    func testUnknownAndEmptyAreNotWake() {
+        XCTAssertFalse(SleepStageVocabulary.isWake(""))
+        XCTAssertFalse(SleepStageVocabulary.isWake("   "))
+        XCTAssertFalse(SleepStageVocabulary.isWake("restless"))
+    }
+
+    /// The regression itself, in the shape the importers use: a night of `awake` + `deep` must count
+    /// only the `deep` span as asleep. Before the fix the `awake` span fell through `!= "wake"` and was
+    /// added to the asleep total, so this asserted 2x the true value.
+    func testAwakeSegmentIsNotCountedAsAsleep() {
+        let segs: [(stage: String, seconds: Int)] = [("awake", 1800), ("deep", 1800)]
+        let asleep = segs.filter { !SleepStageVocabulary.isWake($0.stage) }.reduce(0) { $0 + $1.seconds }
+        XCTAssertEqual(asleep, 1800)
+    }
+
+    /// And the mirror shape: wake time must include the `awake` span, which `== "wake"` dropped.
+    func testWakeTotalIncludesBothSpellings() {
+        let segs: [(stage: String, seconds: Int)] = [("wake", 600), ("awake", 300), ("rem", 1200)]
+        let wake = segs.filter { SleepStageVocabulary.isWake($0.stage) }.reduce(0) { $0 + $1.seconds }
+        XCTAssertEqual(wake, 900)
+    }
+
+    /// INTEGRATION, not the predicate. The tests above pass whether or not the five call sites were
+    /// actually changed — they exercise the rule, not its users. This one exercises a real caller, so
+    /// it is the test that fails if a site is reverted.
+    ///
+    /// The same night as `SleepStagerTests.testHypnogramMetricsAASM`, with the WASO segment spelled
+    /// `awake`. `tst` is computed from a POSITIVE list (`light || deep || rem`) so it is immune either
+    /// way at 1080 s; WASO and the disturbance count are not, and read 0 before the fix.
+    func testWasoAndDisturbancesCountAnAwakeSegment() {
+        let stages = [
+            StageSegment(start: 0, end: 60, stage: "wake"),      // pre-onset, clipped out of WASO
+            StageSegment(start: 60, end: 600, stage: "light"),
+            StageSegment(start: 600, end: 900, stage: "deep"),
+            StageSegment(start: 900, end: 960, stage: "awake"),  // the other spelling — 60 s of WASO
+            StageSegment(start: 960, end: 1200, stage: "rem"),
+        ]
+        let session = SleepSession(start: 0, end: 1200, efficiency: 0.95,
+                                   stages: stages, restingHR: 50, avgHRV: 60)
+        let m = SleepStager.hypnogramMetrics(session)
+        XCTAssertEqual(m.tstS, 1080, accuracy: 1e-9, "sleep total must be unaffected either way")
+        XCTAssertEqual(m.wasoS, 60, accuracy: 1e-9, "an awake segment is wake after sleep onset")
+        XCTAssertEqual(m.disturbances, 1, "and counts as one disturbance")
+    }
+}
diff --git a/Strand/Data/WearableImporter.swift b/Strand/Data/WearableImporter.swift
index 8106b7cfe6..02524d97a3 100644
--- a/Strand/Data/WearableImporter.swift
+++ b/Strand/Data/WearableImporter.swift
@@ -1,4 +1,5 @@
 import Foundation
+import StrandAnalytics
 import WhoopStore
 import StrandImport
 
@@ -131,7 +132,7 @@ enum WearableImporter {
         var asleep = 0
         for seg in segs {
             guard let s = seg["start"] as? Int, let e = seg["end"] as? Int,
-                  let stage = seg["stage"] as? String, stage != "wake" else { continue }
+                  let stage = seg["stage"] as? String, !SleepStageVocabulary.isWake(stage) else { continue }
             asleep += max(0, e - s)
         }
         return min(100, Double(asleep) / Double(end - start) * 100)
diff --git a/Strand/Data/XiaomiImporter.swift b/Strand/Data/XiaomiImporter.swift
index ac63d65e31..c6ebf9b7e3 100644
--- a/Strand/Data/XiaomiImporter.swift
+++ b/Strand/Data/XiaomiImporter.swift
@@ -1,4 +1,5 @@
 import Foundation
+import StrandAnalytics
 import WhoopStore
 import StrandImport
 
@@ -133,7 +134,7 @@ enum XiaomiImporter {
         var asleep = 0
         for seg in segs {
             guard let s = seg["start"] as? Int, let e = seg["end"] as? Int,
-                  let stage = seg["stage"] as? String, stage != "wake" else { continue }
+                  let stage = seg["stage"] as? String, !SleepStageVocabulary.isWake(stage) else { continue }
             asleep += max(0, e - s)
         }
         return min(100, Double(asleep) / Double(end - start) * 100)
diff --git a/android/app/src/main/java/com/noop/analytics/SleepStageVocabulary.kt b/android/app/src/main/java/com/noop/analytics/SleepStageVocabulary.kt
new file mode 100644
index 0000000000..07aec1a0d1
--- /dev/null
+++ b/android/app/src/main/java/com/noop/analytics/SleepStageVocabulary.kt
@@ -0,0 +1,32 @@
+package com.noop.analytics
+
+/**
+ * Which stage strings mean "awake" in a stored hypnogram. Twin of the Swift `SleepStageVocabulary`.
+ *
+ * The tree carries TWO stage vocabularies, and that is deliberate rather than sloppy:
+ *
+ * - **Segment `stage` strings** (hypnogram rows) canonicalise to `"wake"`. [SleepStagerV2] models its
+ *   own states as `"awake"` internally and renames to `"wake"` on the way out for exactly this reason.
+ * - **Minutes-dictionary keys** ([SleepStageTotals]) canonicalise to `"awake"`.
+ *
+ * The bug this closes is the dictionary vocabulary reaching a SEGMENT comparison. Imports do not pass
+ * through [SleepStagerV2]: Oura's phase table is `["deep","light","rem","awake"]`, and generic wearable
+ * JSON carries whatever the source app wrote. A consumer written `stage == "wake"` then silently
+ * misfiles those segments, and — worse — `stage != "wake"` counts them as SLEEP.
+ *
+ * A PREDICATE, deliberately, not a canonicaliser: it fixes the comparisons without rewriting any stored
+ * string, so no persisted hypnogram changes meaning and neither vocabulary above moves.
+ */
+object SleepStageVocabulary {
+
+    /**
+     * True for either spelling of the wake stage, ignoring case and surrounding whitespace.
+     *
+     * Use on a SEGMENT stage string. Minutes dictionaries are keyed `"awake"` by construction and do
+     * not need it. The UI's `canonicalStage` folds through this so the alias rule has one definition.
+     */
+    fun isWake(stage: String): Boolean {
+        val s = stage.trim().lowercase()
+        return s == "wake" || s == "awake"
+    }
+}
diff --git a/android/app/src/main/java/com/noop/analytics/SleepStager.kt b/android/app/src/main/java/com/noop/analytics/SleepStager.kt
index 15c3a863bc..46a54642da 100644
--- a/android/app/src/main/java/com/noop/analytics/SleepStager.kt
+++ b/android/app/src/main/java/com/noop/analytics/SleepStager.kt
@@ -1154,7 +1154,7 @@ object SleepStager {
     internal fun efficiency(start: Long, end: Long, stages: List<StageSegment>): Double {
         val inBed = (end - start).toDouble()
         if (inBed <= 0) return 0.0
-        val wake = stages.filter { it.stage == "wake" }.sumOf { (it.end - it.start).toDouble() }
+        val wake = stages.filter { SleepStageVocabulary.isWake(it.stage) }.sumOf { (it.end - it.start).toDouble() }
         val asleep = maxOf(0.0, inBed - wake)
         return minOf(1.0, asleep / inBed)
     }
@@ -2375,7 +2375,7 @@ object SleepStager {
         var waso = 0.0
         var disturbances = 0
         for (s in segs) {
-            if (s.stage != "wake") continue
+            if (!SleepStageVocabulary.isWake(s.stage)) continue
             val w0 = maxOf(s.start.toDouble(), onset)
             val w1 = minOf(s.end.toDouble(), sptEnd)
             if (w1 > w0) {
diff --git a/android/app/src/main/java/com/noop/analytics/WakeMotionRefinement.kt b/android/app/src/main/java/com/noop/analytics/WakeMotionRefinement.kt
index 8c6e5e9ea4..779553682d 100644
--- a/android/app/src/main/java/com/noop/analytics/WakeMotionRefinement.kt
+++ b/android/app/src/main/java/com/noop/analytics/WakeMotionRefinement.kt
@@ -220,7 +220,7 @@ object WakeMotionRefinement {
         gravByMinute: Map<Long, List<GravitySample>>,
         ticksByMinute: Map<Long, Int>,
     ): List<StageSegment> {
-        if (seg.stage != "wake" || seg.end - seg.start < MIN_WAKE_SEGMENT_SECONDS) return listOf(seg)
+        if (!SleepStageVocabulary.isWake(seg.stage) || seg.end - seg.start < MIN_WAKE_SEGMENT_SECONDS) return listOf(seg)
         val mins = minutes(seg.start, seg.end)
         if (mins.isEmpty()) return listOf(seg)
 
diff --git a/android/app/src/main/java/com/noop/ingest/WearableExportImporter.kt b/android/app/src/main/java/com/noop/ingest/WearableExportImporter.kt
index 77c15e8baf..a4c1de8867 100644
--- a/android/app/src/main/java/com/noop/ingest/WearableExportImporter.kt
+++ b/android/app/src/main/java/com/noop/ingest/WearableExportImporter.kt
@@ -16,6 +16,7 @@ import java.time.LocalDateTime
 import java.time.ZoneOffset
 import java.time.format.DateTimeFormatter
 import java.util.zip.ZipInputStream
+import com.noop.analytics.SleepStageVocabulary
 
 /**
  * Offline file-import of a user's OWN Oura / Fitbit / Garmin data export — fully offline, no cloud
@@ -785,7 +786,7 @@ object WearableExportImporter {
         var asleep = 0L
         for (i in 0 until arr.length()) {
             val o = arr.optJSONObject(i) ?: continue
-            if (o.optString("stage") == "wake") continue
+            if (SleepStageVocabulary.isWake(o.optString("stage"))) continue
             asleep += (o.optLong("end") - o.optLong("start")).coerceAtLeast(0)
         }
         return minOf(100.0, asleep.toDouble() / (end - start) * 100.0)
diff --git a/android/app/src/main/java/com/noop/ingest/XiaomiBandImporter.kt b/android/app/src/main/java/com/noop/ingest/XiaomiBandImporter.kt
index a829e6cd99..2ab0e935f3 100644
--- a/android/app/src/main/java/com/noop/ingest/XiaomiBandImporter.kt
+++ b/android/app/src/main/java/com/noop/ingest/XiaomiBandImporter.kt
@@ -15,6 +15,7 @@ import java.time.Instant
 import java.time.ZoneOffset
 import java.time.format.DateTimeFormatter
 import java.util.zip.ZipInputStream
+import com.noop.analytics.SleepStageVocabulary
 
 /**
  * Imports a **Xiaomi Smart Band (Mi Band)** history from the Mi Fitness app's on-device
@@ -332,7 +333,7 @@ object XiaomiBandImporter {
         var asleep = 0L
         for (i in 0 until arr.length()) {
             val o = arr.optJSONObject(i) ?: continue
-            if (o.optString("stage") == "wake") continue
+            if (SleepStageVocabulary.isWake(o.optString("stage"))) continue
             asleep += (o.optLong("end") - o.optLong("start")).coerceAtLeast(0)
         }
         return minOf(100.0, asleep.toDouble() / (end - start) * 100.0)
diff --git a/android/app/src/main/java/com/noop/ui/SleepStageTimelineLogic.kt b/android/app/src/main/java/com/noop/ui/SleepStageTimelineLogic.kt
index 9635cf8c49..503ea9117e 100644
--- a/android/app/src/main/java/com/noop/ui/SleepStageTimelineLogic.kt
+++ b/android/app/src/main/java/com/noop/ui/SleepStageTimelineLogic.kt
@@ -1,6 +1,7 @@
 package com.noop.ui
 
 import org.json.JSONArray
+import com.noop.analytics.SleepStageVocabulary
 
 /** One persisted per-epoch stage segment (wall-clock unix seconds). */
 internal data class PersistedSegment(val start: Long, val end: Long, val stage: String)
@@ -130,8 +131,10 @@ internal fun displaySmoothed(
  *  repeating the rule, so adding an alias here is all that is needed. Written as code rather than a
  *  KDoc link because the target is private in another file and would not resolve. */
 internal fun canonicalStage(name: String): String {
+    // #979: the alias rule has ONE definition — SleepStageVocabulary. This still folds toward
+    // "awake" because that is the key the stage-colour table and the minutes dictionaries use.
     val n = name.trim().lowercase()
-    return if (n == "wake") "awake" else n
+    return if (SleepStageVocabulary.isWake(n)) "awake" else n
 }
 
 /**
diff --git a/android/app/src/test/java/com/noop/analytics/SleepStageVocabularyTest.kt b/android/app/src/test/java/com/noop/analytics/SleepStageVocabularyTest.kt
new file mode 100644
index 0000000000..2d64c24b53
--- /dev/null
+++ b/android/app/src/test/java/com/noop/analytics/SleepStageVocabularyTest.kt
@@ -0,0 +1,91 @@
+package com.noop.analytics
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+/**
+ * #979 — both spellings of the wake stage occur in stored hypnograms, and five segment comparisons
+ * only recognised one of them.
+ *
+ * The damaging shape is `stage != "wake"`, used to mean "asleep": an imported `"awake"` segment fell
+ * through it and was counted as SLEEP, inflating the efficiency figure. The mirror shape,
+ * `stage == "wake"`, under-counted wake time and made the #987 wake refinement skip those segments.
+ *
+ * Twin of the Swift `SleepStageVocabularyTests`; same cases in the same order.
+ */
+class SleepStageVocabularyTest {
+
+    /** Both spellings are wake. This is the whole point. */
+    @Test fun bothSpellingsAreWake() {
+        assertTrue(SleepStageVocabulary.isWake("wake"))
+        assertTrue(SleepStageVocabulary.isWake("awake"))
+    }
+
+    /** Sleep stages are not wake — the predicate must not swallow the rest of the vocabulary. */
+    @Test fun sleepStagesAreNotWake() {
+        for (s in listOf("deep", "light", "rem")) {
+            assertFalse("$s must not read as wake", SleepStageVocabulary.isWake(s))
+        }
+    }
+
+    /** Imported JSON is not guaranteed tidy; casing and padding must not decide a sleep score. */
+    @Test fun casingAndWhitespaceAreFolded() {
+        assertTrue(SleepStageVocabulary.isWake("Awake"))
+        assertTrue(SleepStageVocabulary.isWake("  WAKE "))
+        assertTrue(SleepStageVocabulary.isWake("\tAwAkE"))
+    }
+
+    /**
+     * An absent or unknown stage is NOT wake, which preserves the existing behaviour of the callers
+     * that treat "anything that is not wake" as asleep. Widening that would be a separate change.
+     */
+    @Test fun unknownAndEmptyAreNotWake() {
+        assertFalse(SleepStageVocabulary.isWake(""))
+        assertFalse(SleepStageVocabulary.isWake("   "))
+        assertFalse(SleepStageVocabulary.isWake("restless"))
+    }
+
+    /**
+     * The regression itself, in the shape the importers use: a night of `awake` + `deep` must count
+     * only the `deep` span as asleep. Before the fix the `awake` span fell through `!= "wake"` and was
+     * added to the asleep total, so this asserted 2x the true value.
+     */
+    @Test fun awakeSegmentIsNotCountedAsAsleep() {
+        val segs = listOf("awake" to 1800, "deep" to 1800)
+        val asleep = segs.filter { !SleepStageVocabulary.isWake(it.first) }.sumOf { it.second }
+        assertEquals(1800, asleep)
+    }
+
+    /** And the mirror shape: wake time must include the `awake` span, which `== "wake"` dropped. */
+    @Test fun wakeTotalIncludesBothSpellings() {
+        val segs = listOf("wake" to 600, "awake" to 300, "rem" to 1200)
+        val wake = segs.filter { SleepStageVocabulary.isWake(it.first) }.sumOf { it.second }
+        assertEquals(900, wake)
+    }
+
+    /**
+     * INTEGRATION, not the predicate. The tests above pass whether or not the five call sites were
+     * actually changed — they exercise the rule, not its users. This one exercises a real caller, so it
+     * is the test that fails if a site is reverted. Twin of the Swift
+     * `testWasoAndDisturbancesCountAnAwakeSegment`.
+     *
+     * `tst` is computed from a POSITIVE list (light/deep/rem) so it is immune either way at 1080 s;
+     * WASO and the disturbance count are not, and read 0 before the fix.
+     */
+    @Test fun wasoAndDisturbancesCountAnAwakeSegment() {
+        val stages = listOf(
+            StageSegment(0L, 60L, "wake"),      // pre-onset, clipped out of WASO
+            StageSegment(60L, 600L, "light"),
+            StageSegment(600L, 900L, "deep"),
+            StageSegment(900L, 960L, "awake"),  // the other spelling — 60 s of WASO
+            StageSegment(960L, 1200L, "rem"),
+        )
+        val session = DetectedSleep(0L, 1200L, 0.95, stages, 50, 60.0)
+        val m = SleepStager.hypnogramMetrics(session)
+        assertEquals("sleep total must be unaffected either way", 1080.0, m.tstS, 1e-9)
+        assertEquals("an awake segment is wake after sleep onset", 60.0, m.wasoS, 1e-9)
+        assertEquals("and counts as one disturbance", 1, m.disturbances)
+    }
+}