What does spline mean?
A spline is an elongated strip, rod, or grooved mechanical fitting, most often used to connect two components while transmitting rotation and limiting unwanted sideways movement. Its teeth or longitudinal grooves interlock with a matching shaft, allowing controlled movement without the abrupt movement associated with a rigid coupling. The word also has a mathematical and computer-graphics meaning: a spline is a smooth curve constructed from calculated segments or controlled by a set of defining points. Such curves are used for interpolation, graphics, typography, and the accurate representation of irregular shapes. The mechanical sense is the traditional one, while the mathematical sense is particularly important in computing and engineering. Although a spline resembles a narrow rib, groove, or flexible strip, its established uses emphasize either a precise mechanical connection or a mathematically continuous curve.
A long, slender strip or rod; a grooved or toothed component that fits with a matching shaft; or, in mathematics and graphics, a smooth curve constructed from defined segments or control points.
"The spline chart used cubic interpolation to display the measured values without abrupt changes in direction."
The mechanical and mathematical senses are distinct technical meanings of the same noun.
To provide, shape, or fit something with a spline.
"The manufacturer splined the shaft so that it would engage securely with the coupling."
This is a specialized and comparatively uncommon verb, used chiefly in mechanical contexts.
The plural is used for individual strips, fittings, shafts, or mathematical curves.
"Several splines in the housing align the rotating components."
From rigid mechanical connections to the smooth curves that shape digital lettering, splines do the work of keeping motion aligned and motion itself fluid.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does spline come from?
The English word developed from an earlier form meaning a slender strip or sliver, probably through Middle English splene; the precise origin of that older form is uncertain. The word was later extended to mechanical fittings with grooves or teeth, whose form resembled such strips. Much more recently, the term was adopted in mathematics for a curve formed from smoothly joined sections.
Related word forms
How spline is actually used
In engineering, “spline” is more precise than a general term for a strip or rib because it commonly indicates a keyed or grooved connection. In mathematics and computer graphics, it is a technical term for a class of piecewise-defined smooth curves. The verb is uncommon and usually means to provide or fit something with a spline.
Easily confused with spline
A splint is a rigid support used to protect or stabilize an injured limb, whereas a spline is an elongated strip, fitting, or mathematical curve.