A translation along a straight line 
and a rotation about 
such that the angle of rotation
is proportional to the translation at each instant.
Also known as a twist.
Screw
See also
Dini's Surface, Helicoid, Rotation, Screw Theorem, Seashell, TranslationExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Screw." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Screw.html