Categories (Lat. Categoriae, Greek Κατηγορίαι Katēgoriai) is a text from Aristotle's Organon that enumerates all the possible kinds of thing which can be the subject or the predicate of a proposition.
The Categories places every object of human apprehension under one of ten categories known to medieval writers as the praedicamenta. They are intended to enumerate everything which can be expressed without composition or structure, thus anything which can be either the subject or the predicate of a proposition.