All 4 Uses

factor
in
The Hitchhiker's Guide to the Galaxy
(Edited)

"Five to one against and falling …" she said, "four to one against and falling … three to one … two … one … probability factor of one to one … we have normality, I repeat we have normality."
Chpt 11

factor = something that affects a result or outcome
"At an Improbability factor," cut in Eddie, who hadn't changed a bit, "of eight million, seven hundred and sixty-seven thousand, one hundred and twenty-eight to one against."
Chpt 18 *
It is therefore clearly an almost infinitely variable figure according to circumstances, since the first two factors vary not only with speed taken as an absolute, but also with awareness of the third factor.
Chpt 34

factors = things that affect a result or outcome
It is therefore clearly an almost infinitely variable figure according to circumstances, since the first two factors vary not only with speed taken as an absolute, but also with awareness of the third factor.
Chpt 34

factor = something that affects 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.