noun 1.a long, narrow, thin strip of wood, metal, etc.; slat.
2.a long, flexible strip of wood or the like, used in drawing curves.
3.Machinery. a.any of a series of uniformly spaced ridges on a shaft, parallel to its axis and fitting inside corresponding grooves in the hub of a gear, etc., to transmit torque.
4.Building Trades. a thin strip of material inserted into the edges of two boards, acoustic tiles, etc., to make a butt joint between them; a feather.
5.Mathematics, Engineering. a function that has specified values at a finite number of points and consists of segments of polynomial functions joined smoothly at these points, enabling it to be used for approximation and interpolation of functions.