-@key{DEL} (@code{delete-backward-char}), which delete only one character at
-a time, and those commands that delete only spaces or newlines. Commands
-that can destroy significant amounts of nontrivial data generally kill.
-The commands' names and individual descriptions use the words @samp{kill}
-and @samp{delete} to say which they do.
+@key{DEL} (@code{delete-backward-char}), which delete only one
+character at a time, and those commands that delete only spaces or
+newlines. Commands that can destroy significant amounts of nontrivial
+data generally do a kill operation instead. The commands' names and
+individual descriptions use the words @samp{kill} and @samp{delete} to
+say which kind of operation they perform.
+
+ On window systems, the most recent kill done in Emacs is also the
+primary selection, if it is more recent than any selection you made in
+another program. This means that the paste commands of other window
+applications copy the text that you killed in Emacs.