(1):
(n.) A note or observation intended to explain, illustrate, or criticise the meaning of a writing, book, etc.; explanation; annotation; exposition.
(2):
(v. t.) To comment on.
(3):
(v. i.) To make remarks, observations, or criticism; especially, to write notes on the works of an author, with a view to illustrate his meaning, or to explain particular passages; to write annotations; - often followed by on or upon.
(4):
(n.) A remark, observation, or criticism; gossip; discourse; talk.