helicoid

Hel"i*coid, a. Etym: [Gr. hélicoïde. See Helix.] 1. Spiral; curved, like the spire of a univalve shell. 2. (Zoöl.) Defn: Shaped like a snail shell; pertaining to the Helicidæ, or Snail family. Helicoid parabola (Math.), the parabolic spiral. Hel"i*coid, n. (Geom.) Defn: A warped surface which may be generated by a straight line moving in such a manner that every point of the line shall have a uniform motion in the direction of another fixed straight line, and at the same time a uniform angular motion about it.

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