Tusk.
1. Formerly applied to the share of a plow.That shortly plow or harrow
Shall pass o'er what was Ismail, and its tusk
Be unimpeded by the proudest mosque.— Don Juan.
2. (Locksmithing.) A sharp projecting point or claw which forms a means of engagement or attachment. Used in the parts of locks in which bolts, tumblers, etc., are thus provided so as to be touched, dropped, raised, etc., by the key, directly or by intermediate devices.
3. (Carpentry.) The beveled shoulder on the back of a tenon of a binding joist, to strengthen it.