SG Heritage Dictionary

Helicoid [Adjective] Webster's Dictionary 1913

1. Spiral; curved, like the spire of a univalve shell.

2. Shaped like a snail shell; pertaining to the Helicidae, or Snail family.

Helicoid [Noun] Webster's Dictionary 1913

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.

Helicoidal [Adjective] Webster's Dictionary 1913

Same as Helicoid.