noun any fish of the genus macrurus. ·see grenadier, 2.
2. rat-tail ·noun the california chimaera. ·see chimaera.
3. rat-tail ·noun an excrescence growing from the pastern to the middle of the shank of a horse.
4. rat-tail ·adj like a rat's tail in form; as, a rat-tail file, which is round, slender, and tapering. ·see ·illust. of file.