cube (n.) Look up cube at Dictionary.com
1550s, from Middle French cube (13c.) and directly from Latin cubus, from Greek kybos "a six-sided die," used metaphorically of dice-like blocks of any sort, also "cake; piece of salted fish; vertebra," of uncertain origin. Beekes points out that "words for dice are often loans" and that "the Lydians claimed to have invented the game" of kybos. The mathematical sense is from 1550s in English (it also was in the ancient Greek word: the Greeks threw with three dice; the highest possible roll was three sixes).
cube (v.) Look up cube at Dictionary.com
1580s in the mathematical sense; 1947 with meaning "cut in cubes," from cube (n.). The Greek verbal derivatives from the noun all referred to dice-throwing and gambling. Related: Cubed; cubing.