diff --git a/GLOSSARY.md b/GLOSSARY.md
index 23a723b..43e448a 100644
--- a/GLOSSARY.md
+++ b/GLOSSARY.md
@@ -48,8 +48,14 @@ The border of a window, by which it is resized.
 
 **Overlay**:
 A decoration drawn over a pane rather than around it: the profile
-selector, the scrollback search field, a confirmation, the size shown
-while resizing, the progress bar, and the scrollbar.
+selector, the scrollback search field, a confirmation, a toast, the size
+shown while resizing, the progress bar, and the scrollbar.
+
+**Toast**:
+A brief overlay saying what has just happened in a pane, such as its
+program copying to the clipboard. It asks nothing and goes away on its own,
+and a pane shows at most one.
+_Avoid_: notification (which is the desktop's), popup, banner, OSD
 
 **Cell**:
 One position in a pane's grid of rows and columns, holding at most one
@@ -118,6 +124,11 @@ A program in a pane reading the clipboard or writing to it, by asking
 harrier to.
 _Avoid_: OSC 52 (except of the escape sequence itself), clipboard request
 
+**Primary selection**:
+The second clipboard, which selecting text copies to and the middle button
+pastes from. "The clipboard" bare is always the other one. Linux only.
+_Avoid_: selection (bare, which is the marked text), X selection
+
 **Clipboard type**:
 One of the forms the clipboard's contents are offered in -- plain text,
 an image, HTML -- each named by a MIME type. A program's **Clipboard