An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A cardinal number, ten times four.

M.E. fourti, O.E. feowertig, from feower, → four, + tig "group of ten" (cf. O.S. fiwartig, Du. veertig, O.H.G. fiorzug, Ger. vierzig, Goth. fidwor tigjus.

Cehel (short form cel); Mid.Pers. cehel "forty;" Av. caθwarəsa(n)t- "forty," from caθwar-, → four, + sant-, sat "ten;" cf. Skt. catvārimśát- "forty."