Information that is widely known, but not acknowledged openly. / (dated) Information that is not widely known, despite being freely available.

Alternative spelling of postoperative

Alternative form of soap opera

Alternative spelling of cooperation

plural of open letter

(intransitive, transitive) To open. / (intransitive) To reveal oneself; to share personal information about oneself; to become communicative. / (intransitive) To commence firing weapons.

A description, usually graphical, showing the major participants or components in a system and their interrelationships.

plural of open mind

Capable of being opened.

(archaic) second-person singular simple present form of open