Double  —adj. 1 consisting of two parts or things; twofold. 2 twice as much or many (double thickness). 3 having twice the usual size, quantity, strength, etc. (double bed). 4 a being double in part. B (of a flower) with two or more circles of petals. 5 ambiguous, deceitful (double meaning; a double life). —adv. 1 at or to twice the amount etc. (counts double). 2 two together (sleep double). —n.