One of the individual entities contributing to a whole
One of the conditions or facts attending an event and having some bearing on it
A component part
The other factor was that he was doing what he had always dreamed of doing.
Another factor was caffeine.
Persia has assumed a comprehensible position as a factor in future Eastern politics.
She didn't factor her transition into a human, either.
This equation does not give us the value of the unknown factor but gives us a ratio between two unknowns.