An Etymological Dictionary of Astronomy and Astrophysics

1. One that actively contributes to the production of a result.
   

2. Math.: Any of the numbers or symbols that when multiplied together form a → product.

Etymology (EN): M.Fr. facteur “agent, representative,” from L. factor
“doer or maker,” from facere “to do” (cf. Fr. faire, Sp. hacer); from PIE base *dhe- “to put, to do;” cf. Skt. dadhati “puts, places;” Av. dadaiti “he puts;”
Hitt. dai- “to place;” Gk. tithenai “to put, set, place;” Lith. deti “to put;” Rus. det’ “to hide,” delat’ “to do;” O.H.G. tuon; Ger. tun; O.S., O.E. don “to do.”

Etymology (PE): Karvand, from kar- root of Mod.Pers. verb kardan “to do, to make” (Mid.Pers. kardan; O.Pers./Av. kar- “to do, make, build;” Av. kərənaoiti “he makes;” cf. Skt. kr- “to do, to make,” krnoti “he makes, he does,” karoti “he makes, he does,” karma “act, deed;” PIE base k^wer- “to do, to make”)

• -vand a suffix forming adjectives and agent nouns.