quadruple (v.)
late 14c., from Middle French quadrupler, from Late Latin quadruplare "make fourfold, multiply by four," from Latin quadruplus (adj.) "quadruple, fourfold" (see quadruple (adj.)).
quadruple (adj.)
1550s, from Middle French quadruple (13c.), from Latin quadruplus "fourfold," from quadri- "four" (see quadru-) + -plus "-fold" (see -plus).