Definition
Divisor
The nonzero quantity that another quantity is divided by.
What it means
The divisor tells either how many equal groups to make or the size of each group, depending on the problem. It cannot be zero.
Remember it
Dividend ÷ divisor = quotient: the divisor follows the division sign.
Example
In 84 ÷ 7 = 12, 7 is the divisor. It can mean making 7 equal groups or making groups of 7, depending on the story.
Watch for
Zero cannot be a divisor, because division by zero is not defined in ordinary arithmetic.
Common mix-up
In a calculation, 7 is the divisor in both 84 ÷ 7 and 85 ÷ 7. In factor language, 7 is a divisor of 84 but not of 85 because 85 ÷ 7 has a remainder.
Exact meaning
In a division expression a ÷ b, b is the divisor: the nonzero quantity by which the dividend is divided.