\Fil"let\, n. [OE. filet, felet, fr. OF. filet thread,
fillet of meat, dim. of fil a thread, fr. L. filum. See
{Fille} a row.]
1. A little band, especially one intended to encircle the
   hair of the head.
         A belt her waist, a fillet binds her hair. --Pope.
2. (Cooking) A piece of lean meat without bone; sometimes, a
   long strip rolled together and tied.
Note: A fillet of beef is the under side of the sirlom; also
      called tenderloin. A fillet of veal or mutton is the
      fleshy part of the thigh. A fillet of fish is a slice
      of flat fish without bone. ``Fillet of a fenny snake.''
      --Shak.
3. A thin strip or ribbon; esp.:
   (a) A strip of metal from which coins are punched.
   (b) A strip of card clothing.
   (c) A thin projecting band or strip.
4. (Mach.) A concave filling in of a re["e]ntrant angle where
   two surfaces meet, forming a rounded corner.
5. (Arch.) A narrow flat member; especially, a flat molding
   separating other moldings; a reglet; also, the space
   between two flutings in a shaft. See Illust. of {Base},
   and {Column}.
6. (Her.) An ordinary equaling in breadth one fourth of the
   chief, to the lowest portion of which it corresponds in
   position.
7. (Mech.) The thread of a screw.
8. A border of broad or narrow lines of color or gilt.
9. The raised molding about the muzzle of a gun.
10. Any scantling smaller than a batten.
11. (Anat.) A fascia; a band of fibers; applied esp. to
    certain bands of white matter in the brain.
12. (Man.) The loins of a horse, beginning at the place where
    the hinder part of the saddle rests.
{Arris fillet}. See under {Arris}.

\Fil"let\, v. t. [imp. & p. p. {Filleted}; p. pr. & vb.
n. {Filleting}.]
To bind, furnish, or adorn with a fillet.