a curve that is the locus of a point that moves outward with uniform speed along a vector, beginning at the origin, while the vector rotates about the origin with uniform angular velocity. Equation (in polar coordinates): r = aθ.
British Dictionary definitions for spiral-of-archimedes
spiral of Archimedes
(maths) a spiral having the equation r = aθ, where a is a constant. It is the locus of a point moving to or from the origin at a constant speed along a line rotating around that origin at a constant speed