(logic) A formal deductive system which extends first-order logic by the ability to quantify over unary predicates over individual members of the universe of discourse.

A Roman Catholic lay fraternity for men.

plural of monadic second-order logic

Neat and tidy; possessing order. / Methodical or systematic. / Peaceful; well-behaved. / Being on duty; keeping order; conveying orders.

A hospital attendant given a variety of non-medical duties. / (military) A soldier who carries out minor tasks for a superior officer.

(now rare) According to good order or practice; appropriately, in a well-behaved or orderly (adjective) way. / (obsolete) In order; in a particular order or succession; with a suitable arrangement.

The fact of having a regular, proper and systematic arrangement. / Orderly behaviour.

plural of orderly

Devoid of order or arrangement; chaotic.

Absence of order; chaos.