/hee"liks/ , n. , pl. helices /hel"euh seez'/ , helixes .
1. a spiral.
2. Geom. the curve formed by a straight line drawn on a plane when that plane is wrapped around a cylindrical surface of any kind, esp. a right circular cylinder, as the curve of a screw. Equation: x = a sin(t), y = a cos(t), z = b t.
3. Archit.
a. a spiral ornament.
b. (in a Corinthian capital) either of two scrolls issuing from a cauliculus. Cf. Corinthian (def. 2).
4. Anat. the curved fold forming most of the rim of the external ear. See diag. under ear .
5. Biochem. See alpha helix .
[ 1555-65; hélix anything twisted; cf. helíssein to turn, twist, roll ]