diff --git a/src/runtime/metrics/description.go b/src/runtime/metrics/description.go
index bc2e088..9d3611b 100644
--- a/src/runtime/metrics/description.go
+++ b/src/runtime/metrics/description.go
@@ -58,7 +58,7 @@
 	},
 	{
 		Name:        "/gc/cycles/forced:gc-cycles",
-		Description: "Count of completed forced GC cycles.",
+		Description: "Count of completed GC cycles forced by the application.",
 		Kind:        KindUint64,
 		Cumulative:  true,
 	},
@@ -94,28 +94,33 @@
 		Kind:        KindFloat64Histogram,
 	},
 	{
-		Name:        "/memory/classes/heap/free:bytes",
-		Description: "Memory that is available for allocation, and may be returned to the underlying system.",
-		Kind:        KindUint64,
+		Name: "/memory/classes/heap/free:bytes",
+		Description: "Memory that is completely free and eligible to be returned to the underlying system, " +
+			"but has not been. This metric is the runtime's estimate of free address space that is backed by " +
+			"physical memory.",
+		Kind: KindUint64,
 	},
 	{
 		Name:        "/memory/classes/heap/objects:bytes",
-		Description: "Memory occupied by live objects and dead objects that have not yet been collected.",
+		Description: "Memory occupied by live objects and dead objects that have not yet been marked free by the garbage collector.",
 		Kind:        KindUint64,
 	},
 	{
-		Name:        "/memory/classes/heap/released:bytes",
-		Description: "Memory that has been returned to the underlying system.",
-		Kind:        KindUint64,
+		Name: "/memory/classes/heap/released:bytes",
+		Description: "Memory that is completely free and has been returned to the underlying system. This " +
+			"metric is the runtime's estimate of free address space that is still mapped into the process, " +
+			"but is not backed by physical memory.",
+		Kind: KindUint64,
 	},
 	{
-		Name:        "/memory/classes/heap/stacks:bytes",
-		Description: "Memory allocated from the heap that is occupied by stacks.",
-		Kind:        KindUint64,
+		Name: "/memory/classes/heap/stacks:bytes",
+		Description: "Memory allocated from the heap that is reserved for stack space. Not all of it is necessarily " +
+			"simultaneously in use, but it may not be used for any other purpose.",
+		Kind: KindUint64,
 	},
 	{
 		Name:        "/memory/classes/heap/unused:bytes",
-		Description: "Memory that is unavailable for allocation, but cannot be returned to the underlying system.",
+		Description: "Memory that is reserved for heap objects but is otherwise not currently used to hold heap objects.",
 		Kind:        KindUint64,
 	},
 	{
diff --git a/src/runtime/metrics/doc.go b/src/runtime/metrics/doc.go
index e340f3d..f58cdcd 100644
--- a/src/runtime/metrics/doc.go
+++ b/src/runtime/metrics/doc.go
@@ -48,7 +48,7 @@
 		Count of completed GC cycles generated by the Go runtime.
 
 	/gc/cycles/forced:gc-cycles
-		Count of completed forced GC cycles.
+		Count of completed GC cycles forced by the application.
 
 	/gc/cycles/total:gc-cycles
 		Count of all completed GC cycles.
@@ -69,22 +69,29 @@
 		Distribution individual GC-related stop-the-world pause latencies.
 
 	/memory/classes/heap/free:bytes
-		Memory that is available for allocation, and may be returned
-		to the underlying system.
+		Memory that is completely free and eligible to be returned to
+		the underlying system, but has not been. This metric is the
+		runtime's estimate of free address space that is backed by
+		physical memory.
 
 	/memory/classes/heap/objects:bytes
 		Memory occupied by live objects and dead objects that have
-		not yet been collected.
+		not yet been marked free by the garbage collector.
 
 	/memory/classes/heap/released:bytes
-		Memory that has been returned to the underlying system.
+		Memory that is completely free and has been returned to
+		the underlying system. This metric is the runtime's estimate of
+		free address space that is still mapped into the process, but
+		is not backed by physical memory.
 
 	/memory/classes/heap/stacks:bytes
-		Memory allocated from the heap that is occupied by stacks.
+		Memory allocated from the heap that is reserved for stack
+		space. Not all of it is necessarily simultaneously in use, but
+		it may not be used for any other purpose.
 
 	/memory/classes/heap/unused:bytes
-		Memory that is unavailable for allocation, but cannot be
-		returned to the underlying system.
+		Memory that is reserved for heap objects but is otherwise not
+		currently used to hold heap objects.
 
 	/memory/classes/metadata/mcache/free:bytes
 		Memory that is reserved for runtime mcache structures, but