| 释义 |
hel·i·coid
I. \ˈheləˌkȯid\ adjective
or hel·i·coi·dal \|helə|kȯidəl\
Etymology: helicoid from Greek helikoeidēs of spiral form, from helik- helic- + -oeidēs -oid; helicoidal from helicoid + -al
1. : having the properties of a helicoid
2. : forming or arranged in a spiral
< helicoid inflorescence >
specifically of a gastropod shell : having the form of a flat coil or flattened spiral
< Planorbis is characterized by a helicoid shell >
II. noun
(-s)
: a surface resembling that of a screw thread that is generated by a curve which rotates about a straight line and moves in the direction of the line with a velocity whose ratio to the velocity of rotation is constant |