helicoid

adjective

shaped like, or coiled in the form of, a spiral, as the shell of a snail or certain inflorescences

Etymology: Gr helikoeidēs < helix, a spiral + -eidēs, -oid

noun

Geom. a surface generated by the rotation of a plane or twisted curve about a fixed line so that each point of the curve traces out a circular helix with the fixed line as axis