ABCDEFGHIJKLMNOPQRSTUVWXYZ Definition of Divisible more ... When dividing by a certain number gets a whole number answer. Example: 15 is divisible by 3, because 15 ÷ 3 = 5 (a whole number) But 9 is not divisible by 2 because 9 ÷ 2 = 4½ (not a whole number) Divisibility Rules