An Etymological Dictionary of Astronomy and Astrophysics

Any of the four main → proposition forms treated in Aristotle’s → syllogism:

The A form (universal affirmative): All P’s are Q’s,

The E form (universal negative): No P’s are Q’s,

The I form (particular affirmative): Some P’s are Q’s, and

The O form (particular negative) Some P’s are not Q’s.

See also: Greek philosopher Aristotle (384-322 BC); → form.