exponent /ikspō″nənt/ , a superscript on a number that indicates how many times a number is to be multiplied by itself (for example, 34 = 3 × 3 × 3 × 3 = 81). In medical or scientific reports, powers of 10 are commonly used to indicate very large or very small numbers, such as in the examples 106 representing 1,000,000 or 10-6 representing 1/1,000,000. Exponents also are indicated by prefixes, such as mega- for 106 and micro- for 10-6.