Entry 2 senses · 2 variants Webster, 1913 Incisor /ĭnˌ-sīz'-ẽr/ · In·ci·sor · IPA /ɪnˈsaɪ.zə(ɹ)/ n. a. 01 n. One of the teeth in front of the canines in either jaw; an incisive tooth. See Tooth. 1. One of the teeth in front of the canines in either jaw; an incisive tooth. See Tooth.(Anat.) See: Tooth 02 a. Adapted for cutting; of or pertaining to the incisors; incisive; as, the incisor nerve; an incisor foramen; an incisor tooth. 1. Adapted for cutting; of or pertaining to the incisors; incisive; as, the incisor nerve; an incisor foramen; an incisor tooth.