Know how to use "fewer" and "less"? Find out.
c.1400, from Old French composite, from Latin compositus "placed together," past participle of componere "to put together, to collect a whole from several parts," from com- "together" (see com-) + ponere "to place" (see position (n.)). The noun is attested from c.1400. Composite number is from 1730s.