HELIX, in geometry, a spiral line. See SPIRAL.—The word is Greek, ἕλξ, and literally signifies "a wreath or winding;" of ἕλκεσθαι, "I environ."
In architecture, some authors make a difference between the helix and the spiral. A stair-case, 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.