-If the string is bound to a keycode, its value (greater than zero) is returned.
-If no keycode is bound, zero is returned.
-If the string conflicts with longer strings
-which are bound to keys, \-1 is returned.
+.B \%key_defined
+returns the first key code to which
+.I definition
+is bound if any exists.
+If none does,
+it returns
+.BR 0 "."
+If
+.I definition
+is a prefix of another binding,
+.B \%key_defined
+returns
+.BR \-1 "."
+.SH EXTENSIONS
+.B \%define_key
+is an
+.I \%ncurses
+extension.