Base Base (b[=a]s), v. t. [imp. & p. p. Based (b[=a]sd); p. pr. & vb. n. Basing.] [From Base, n.] To put on a base or basis; to lay the foundation of; to found, as an argument or conclusion; -- used with on or upon. --Bacon., Based Based, p. p. & a. 1. Having a base, or having as a base; supported; as, broad-based. 2. [See Base, n., 18-21.] Wearing, or protected by, bases. [Obs.] ``Based in lawny velvet.' --E. Hall.