a. [ From Helix. ] Of or pertaining to, or in the form of, a helix; spiral; as, a helical staircase; a helical spring. -- Hel"i*cal*ly, adv. [1913 Webster]

‖n. [ L., the marigold, fr. Gr. &unr_; a kind of plant. ] (Bot.) A genus of composite plants, with shining, commonly white or yellow, or sometimes reddish, radiated involucres, which are often called “everlasting flowers.” [ 1913 Webster ]

a. [ Helix + -form. ] Having the form of a helix; spiral. [ 1913 Webster ]

n. (Chem.) A glucoside obtained as a white crystalline substance by partial oxidation of salicin, from a willow (Salix Helix of Linnaeus.) [ 1913 Webster ]

a. (Anat.) Curled; spiral; helicoid; -- applied esp. to certain arteries of the penis. [ 1913 Webster ]

n. [ Helix + -graph. ] An instrument for drawing spiral lines on a plane. [ 1913 Webster ]

a. [ Gr. &unr_;; &unr_;, &unr_;, spiral + &unr_; shape: cf. F. hélicoïde. See Helix. ] [ 1913 Webster ]

1. Spiral; curved, like the spire of a univalve shell. [ 1913 Webster ]

2. (Zool.) Shaped like a snail shell; pertaining to the Helicidae, or Snail family. [ 1913 Webster ]

Helicoid parabola (Math.), the parabolic spiral. [ 1913 Webster ]

n. (Geom.) A warped surface which may be generated by a straight line moving in such a manner that every point of the line shall have a uniform motion in the direction of another fixed straight line, and at the same time a uniform angular motion about it. [ 1913 Webster ]

a. Same as Helicoid. -- Hel`i*coid"al*ly, adv. [1913 Webster]

prop. n. [ L., fr. Gr. "Elikw`n.] A mountain in Bœotia, in Greece, supposed by the Greeks to be the residence of Apollo and the Muses. [1913 Webster]

From Helicon's harmonious springs
A thousand rills their mazy progress take. Gray. [1913 Webster]