Instead of giving you a confusing definition first, I will just you an example:
1×24=24
2×12=24
3×8= 24
4×6=24
The factors of 24 are 1,2,3,4,6,8,12,24
So you can deduce that factors of a number are the numbers which can be multiplied to get the said number.
You can also say that factors of a number can be divided by the said number without living a remainder