helicoid noun & adjective. ['hɛlɪkɔɪd, 'hi:-] L17.
[Greek helikoeidēs, from HELIX: see -OID.]
A. noun.
1. An object of spiral shape. rare. L17.

2. Geometry. A surface generated by moving a straight line in the direction of an axis about which it simultaneously rotates. M19.
b. adjective. Esp. of a shell, inflorescence, etc.: having the form of a helix; spirally coiled. E18.
helicoid parabola = parabolic spiral s.v. PARABOLIC adjective 2.

■ heli'coidal adjective = HELICOID adjective M19.

■ heli'coidally adverb M20.

[TahlilGaran] English Dictionary ▲