@kbd{Hyper-} (usually written @kbd{H-} for short). @xref{User Input,
Hyper}.
+@item Iff
+``Iff'' means ``if and only if.'' This terminology comes from
+mathematics.
+
@item Inbox
An inbox is a file in which mail is delivered by the operating system.
Rmail transfers mail from inboxes to Rmail files (q.v.@:) in which the