'grand unified theory' definitions:

Definition of 'grand unified theory'

From: GCIDE

grand unified theory \grand unified theory\, grand unification theory \grand unification theory\n. (Theoretical physics) Any of a class of physics theories that attempts to explain the electroweak forces, stong force, and gravitation within a single mathematical conceptual scheme. In the 1990's {string theory} and superstring theory were prominent examples. Abbreviated GUT, plural GUTs. [PJC]