All 4 Uses

factor
in
Live Free or Die, by John Ringo
(Edited)

But I doubt they have factored in the humans.†
p. 107.7

factored = considered (for affect on a result or outcome)
Given that the current output of the Very Large Array is only eight point six times ten to the sixth joules per second, even factoring for the projected rate of increase, subtracting anticipated heat dissipation, it will require some six months to observe noticeable heating, much less melting, of the material.
p. 117.3 *

factoring = considering (the affect on a result or outcome)
Heavy metal contamination on the edges might have been the deciding factor in its failure.†
p. 256.4

factor = thing that affects a result or outcome
There were a bunch of people predisposed to cancer and other factors that weren't caught in time that were ...gainfully employed and productive members of society?†
p. 348.1 *

factors = things that affect a result or outcome

Definitions:

(1) (factor as in: It was the deciding factor.)
something that affects a result or outcome

You also may encounter x-factor or x factor--meaning "the most important thing that influences a result or outcome."
(2) (factor as in: factor it into your thinking)
include consideration of
(3) (meaning too rare to warrant focus)
There are many specialized meanings in fields such as mathematics, business, finance, biology, and grammar.