—n. 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. Mach. 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.
b. See feather key. 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. Math.,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.
—v.t. Mach. 1. to provide with a spline or key.
2. to provide with a keyway.