In general, a factor is a term that exactly divides a given term.
Example 1: 3 is a factor of 12x7y2z [since (3)(4x7y2z) = 12x7y2z].
Example 2: x3 is a factor of 12x7y2z [since (x3)(12x4y2z) = 12x7y2z].
Example 3: 6z is a factor of 12x7y2z [since (6z)(2x7y2) = 12x7y2z].
Example 4: z3 is NOT a factor of 12x7y2z.
In terms of numbers, a factor is a natural number that exactly divides a given natural number.
Example 1: 6 is a factor of 12 [since (6)(2) = 12].
Example 2: 12 is a factor of 12 [since (12)(1) = 12].
Example 3: 8 is NOT a factor of 12. [since 12 ÷ 8 = 1.5].