Capsize \Cap*size"\, v. t. & i. [imp. & p. p. {Capsized}; p. pr. & vb. n. {Capsizing}.] [Cf. Sp. cabecear to nod, pitch, capuzar, chapuzar, to sink (a vessel) by the head; both fr. L. caput head.] To upset or overturn, as a vessel or other body. But what if carrying sail capsize the boat? --Byron.