n.
Pronunciation: ' k ō - ˌ fak-t ə r
Function: noun
Date: 1885
1 : the signed minor of an element of a square matrix or of a determinant with the sign positive if the sum of the column number and row number of the element is even and with the sign negative if it is odd
2 : a substance that acts with another substance to bring about certain effects especially : COENZYME
3 : something (as diet or a virus) that acts with or aids another factor in causing disease