Spline (?), n. 1. A rectangular piece fitting 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; a feather; also, sometimes, a groove to receive such a rectangular piece.

2. A long, flexble piece of wood sometimes used as a ruler.

Spline (?), n. 1. A rectangular piece fitting 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; a feather; also, sometimes, a groove to receive such a rectangular piece.

2. A long, flexble piece of wood sometimes used as a ruler.

• 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.
  
• 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.
  
• (mathematics, computing) Any of a number of smooth curves used to join points.