| the largest number that is a common divisor of a given set of numbers. Abbreviation: G.C.D. |
| great·est common divisor (grā'tĭst) n. Abbr. gcd The largest number that divides evenly into each of a given set of numbers. Also called greatest common factor, highest common factor. |
| high·est common factor (hī'ĭst) n. Abbr. hcf See greatest common divisor. |