perfect square A number that is the product of two equal whole numbers, e.g. 1 = 1 × 1, 4 = 2 × 2, 9 = 3 × 3, 16 = 4 × 4, 25 = 5 × 5. Related categories TYPES OF NUMBERS MATHEMATICS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |