Entry 2 senses Webster, 1913 Numerator /no͞oʹ-mər-ā'-tər/ · Nu·mer·a·tor · IPA /ˈnuː.məɹˌeɪ̯.təɹ/ 01 n. One who numbers. 1. One who numbers. 2. The term in a fraction which indicates the number of fractional units that are taken.(Math.)