Ar·ris n.  Arch. The sharp edge or salient angle formed by two surfaces meeting each other, whether plane or curved; -- applied particularly to the edges in moldings, and to the raised edges which separate the flutings in a Doric column.
 Arris fillet, a triangular piece of wood used to raise the slates of a roof against a chimney or wall, to throw off the rain. --Gwilt.
 Arris gutter, a gutter of a V form fixed to the eaves of a building. --Gwilt.
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 Fil·let n.
 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.”
 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 reëntrant 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.