Definition of helix in English:


Line breaks: helix
Pronunciation: /ˈhiːlɪks

noun (plural helices /ˈhiːlɪsiːz, ˈhɛl-/)

1An object having a three-dimensional shape like that of a wire wound uniformly in a single layer around a cylinder or cone, as in a corkscrew or spiral staircase.
More example sentences
  • They found that DNA consists of two connected twisted strands in the shape of a helix.
  • The excess is carefully cut away to fabricate the helix shape.
  • A television monitor showed what was inside: a glowing ball of gas surrounded by a metal helix.
spiral, coil, curl, corkscrew, twist, twirl, loop, gyre, whorl, scroll, curlicue, convolution
technical volute, volution
1.1 Geometry A curve on a conical or cylindrical surface which would become a straight line if the surface were unrolled into a plane.
More example sentences
  • A template in the shape of a narrow right-angle triangle is wrapped around the cylinder to be threaded, and the hypotenuse of the triangle forms the line of the helix.
  • The conical helix of their upward spiral against the flat blue sky is completely hypnotic.
1.2 Biochemistry An extended spiral chain of atoms in a protein, nucleic acid, or other polymeric molecule.
More example sentences
  • The gray bands indicate the helix regions of the protein.
  • DNA molecules in nature are built from two complementary strands that bind to form the double helix.
  • The double helix of DNA is held together by hydrogen bonds.
1.3 Architecture A spiral ornament.
More example sentences
  • Ross Lovegrove's stairway, with its helix profile, is part of a new tendency by designers to borrow forms from nature.
2 Anatomy The rim of the external ear.
More example sentences
  • The ear print on the safe had a circular mark at the top of the ear helix.
  • Decrease oxygen saturation in blood in the helix of the ear by using an ear oximeter.


mid 16th century (in the architectural sense 'spiral ornament'): via Latin from Greek.

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