diff --git a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
index e90053fd8ae..82ca6735b01 100644
--- a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
+++ b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
@@ -14,7 +14,7 @@ public actual abstract class AbstractMutableCollection<E> protected actual const
 
     // Bulk Modification Operations
     /**
-     * Adds all of the elements in the specified collection to this collection.
+     * Adds all of the elements of the specified collection to this collection.
      *
      * @return `true` if any of the specified elements was added to the collection, `false` if the collection was not modified.
      */
diff --git a/runtime/src/main/kotlin/kotlin/native/concurrent/Annotations.kt b/runtime/src/main/kotlin/kotlin/native/concurrent/Annotations.kt
index 2cfed5b8ebe..a56ea0b774d 100644
--- a/runtime/src/main/kotlin/kotlin/native/concurrent/Annotations.kt
+++ b/runtime/src/main/kotlin/kotlin/native/concurrent/Annotations.kt
@@ -6,9 +6,10 @@
 package kotlin.native.concurrent
 
 /**
- * Top level variable or object is thread local, and so could be mutable.
- * One may use this annotation as the stopgap measure for singleton
- * object immutability.
+ * Marks a top level variable with a backing field or an object as thread local.
+ * The object remains mutable and it is possible to change its state,
+ * but every thread will have a distinct copy of this object,
+ * so changes in one thread are not reflected in another.
  *
  * PLEASE NOTE THAT THIS ANNOTATION MAY GO AWAY IN UPCOMING RELEASES.
  */
@@ -17,7 +18,9 @@ package kotlin.native.concurrent
 public actual annotation class ThreadLocal
 
 /**
- * Top level variable is immutable and so could be shared.
+ * Marks a top level variable with a backing field or an object as immutable.
+ * It is possible to share such object between multiple threads, but it becomes deeply frozen,
+ * so no changes can be made to its state or the state of objects it refers to.
  *
  * PLEASE NOTE THAT THIS ANNOTATION MAY GO AWAY IN UPCOMING RELEASES.
  */
diff --git a/runtime/src/main/kotlin/kotlin/test/Annotation.kt b/runtime/src/main/kotlin/kotlin/test/Annotation.kt
index d96ff9bf333..92ab8b15f8a 100644
--- a/runtime/src/main/kotlin/kotlin/test/Annotation.kt
+++ b/runtime/src/main/kotlin/kotlin/test/Annotation.kt
@@ -24,13 +24,13 @@ public annotation class BeforeClass
 public annotation class AfterClass
 
 /**
- * Marks a function to be executed before a test.
+ * Marks a function to be invoked before each test.
  */
 @Target(AnnotationTarget.FUNCTION)
 public actual annotation class BeforeTest
 
 /**
- * Marks a function to be executed after a test.
+ * Marks a function to be invoked after each test.
  */
 @Target(AnnotationTarget.FUNCTION)
 public actual annotation class AfterTest