Abbrev Mode

desc	command	keystroke
define a global abbrev	add-global-abbrev	C-x a g
define a local (mode-specific) abbrev with	add-mode-abbrev	C-x a l
define a word in the buffer (ie inverse)	inverse-add-global-abbrev	C-x a i g
cancel an expansion	quoted-insert	C-q
define an abbrev from minibuffer	define-global-abbrev
save abbrevs when in abbrev mode	edit-abbrevs-redefine	C-c C-c

Editing abbrevs

desc	command
write lisp file of user-created abbrev definitions	write-abbrev-file
edit in-memory abbrev definitions	edit-abbrevs
read definitions file	read-abbrev-file