\Rat"-tail`\, a.
Like a rat's tale in form; as, a rat-tail file, which is
round, slender, and tapering. See Illust. of {File}.

\Rat"-tail`\, n.
1. (Far.) pl. An excrescence growing from the pastern to the
   middle of the shank of a horse.

2. (Zo["o]l.)
   (a) The California chim[ae]ra. See {Chim[ae]ra}.
   (b) Any fish of the genus {Macrurus}. See {Grenadier}, 2.