HELICOID

Hel″i‐coid (?), a. [[Gr. �; ἕλιξ, -ικοσ, spiral + � shape: cf. F. hélicoïde. See Helix.]] 1. 1. Spiral; curved, like the spire of a univalve shell.
2. 2. (Zoöl.) Shaped like a snail shell; pertaining to the Helicidæ, or Snail family.
Helicoid parabola (Math.), the parabolic spiral.