Pronunciation: (thē'ur-um, thēr'um), [key]
1. Math.a theoretical proposition, statement, or formula embodying something to be proved from other propositions or formulas.
2. a rule or law, esp. one expressed by an equation or formula.
3. Logic.a proposition that can be deduced from the premises or assumptions of a system.
4. an idea, belief, method, or statement generally accepted as true or worthwhile without proof.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.