1. (a.) Like a rat's tail in form; as, a rat-tail file, which is round, slender, and tapering.

2. (n.) An excrescence growing from the pastern to the middle of the shank of a horse.

3. (n.) The California chimaera. See Chimaera.

4. (n.) Any fish of the genus Macrurus. See Grenadier, 2.