in Geometry, a spiral line. See Spiral.

The word is Greek, ἑλίξ, and literally signifies "a wreath or winding;" of ἑλίξινος ἐνεργεῖον, "I environ."

In architecture, some authors make a difference between the helix and the spiral. A staircase, according to Daviler, is in a helix, or is helical, when the stairs or steps wind round a cylindrical newel; whereas the spiral winds round a cone, and is continually approaching nearer and nearer its axis.

HELIX is also applied, in Architecture, to the caulicles or little volutes under the flowers of the Corinthian capital; called also uricle.

in Anatomy, is the whole circuit or extent of the auricle or border of the ear outwards. In opposition to which, the inner protuberance surrounded thereby, and answering thereto, is called antelix. See Anatomy, No. 141.

the Snail, a genus of shell-fish belonging to the order of vermes testacea. See Conchology Index.