Noun, pl. incisors
1. Are the front teeth present in most heterodont mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). (wikipedia.org)
3. A narrow-edged tooth at the front of the mouth, adapted for cutting. In humans there are four incisors in each jaw. (Google Dictionary)
Word origin: From Medieval Latin incisor “a cutting tooth,” literally “that which cuts into,” from Latin incisus, past participle of incidere.