Merriam-Webster's Collegiate® Dictionary, 11th Edition
TUSK
I. noun
Etymology: Middle English, alteration of tux, from Old English tūx; akin to Old English tūsc tush Date: before 12th century an elongated greatly enlarged tooth (as of an elephant or walrus) that projects when the mouth is closed and serves especially for digging food or as a weapon, one of the small projections on a tusk tenon, tusked adjective tusklike adjective
II. transitive verb
Date: 1629
to dig up with a tusk