spline

noun

1. A long, thin piece of metal or wood.
2. A strip of wood or other material inserted into grooves in each of two pieces of wood to provide additional surface for gluing.
3. A flexible strip of metal or other material, that may be bent into a curve and used in a similar manner to a ruler to draw smooth curves between points.
4. Any of a number of smooth curves used to join points.

   “However, it should be possible to give more sophisticated spherical spline curves based on the de Castaljau method that are computed using multiple slerps between pairs of points and which work well for arbitrary knot positions (indeed, knot insertion methods for spline curves should suffice for this, cf Farin [1993])”

   “These conditions provide a framework which encompasses some notable approximation kernels including splines, so-called cardinal functions, and many radial basis functions such as the Gaussians and general multiquadrics.”

5. A ridge or tooth on a drive shaft that meshes with a corresponding groove in a mating piece and transfers torque to it, maintaining the angular correspondence between the pieces; either the ridge or the groove, as part of a set of both (splines); the whole set of ridges and grooves.
6. A rectangular piece that fits grooves like key seats in a hub and a shaft, so that while the one may slide endwise on the other, both must revolve together.

   “Near-synonym: feather”

verb

1. To smooth (a curve or surface) by means of a spline.
2. To fit with a spline.

   “Machining a straight spline with a lathe. Sometimes the task of splining a shaft comes up during a repair. Instead of sending out the job, use this setup to mill the splines on a lathe.”

3. To fasten to or together with a spline.

   “Engineers did not think two crankshafts could be synchronized. Wood, by splining the shafts in each gear box, proved it could be done.”

   “These packs can be holding or driving devices, depending on what they are splined to.”

   “Splined bars are a big recent trend. Originally used in racing, the idea is to have a straight torsion bar with the ends splined like an axle and separate arms that fit on each end to mount the end links”