All 5 Uses

factor
in
Hopeless, by Colleen Hoover
(Auto-generated)

I think maybe it was the deciding factor in a decision she had wanted to make for a long time.†
p. 243.1 *

factor = thing that affects a result or outcome
Six's sense of humor and straightforward personality are huge factors in why we get along so well.†
p. 34.2
"Don't factor me into this," he says, turning back around.†
p. 77.6
I wish it wasn't, but sometimes factors other than love make these decisions for you.†
p. 311.7
Factors like hate.†
p. 311.8

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.