Definition of spline
1
: a thin wood or metal strip used in building construction
2
: a key that is fixed to one of two connected mechanical parts and fits into a keyway in the other;
also
: a keyway for such a key
3
: a function that is defined on an interval, is used to approximate a given function, and is composed of pieces of simple functions defined on subintervals and joined at their endpoints with a suitable degree of smoothness
