Webster's Revised Unabridged Dictionary · 1913

Tusk

Tusk (tusk) , noun

(Zoology) Same as Torsk.

Tusk , noun

[Old English tusk, the same word as tusch, Anglo-Saxon tusc. See Tush a tooth.]

1.
(Zoology) One of the elongated incisor or canine teeth of the wild boar, elephant, etc.; hence, any long, protruding tooth.
2.
(Zoology) A toothshell, or Dentalium; -- called also tusk-shell.
3.
(Carpentry) A projecting member like a tenon, and serving the same or a similar purpose, but composed of several steps, or offsets. Thus, in the illustration, a is the tusk, and each of the several parts, or offsets, is called a tooth.

Tusk (tusk) , intransitive verb

To bare or gnash the teeth. [Obsolete]