helix

helix — noun

1. A three-dimensional curve that winds around a central line or surface, with each

1.nounB2
Definition

A three-dimensional curve that winds around a central line or surface, with each point staying at the same distance from the centre — seen in shapes such as springs, spiral staircases, and the DNA molecule.

Example

The DNA molecule has the shape of a double helix.

collocation: double helix

Sana drew a helix to show how the staircase twisted around a central pillar.

Common collocations
  • double helix
  • helix shape
  • form a helix
  • twist into a helix
Synonyms
  • spiral

    Used loosely for helix in everyday speech, though a spiral is technically a flat curve that grows outward from a centre point.

  • coil

    Emphasises the circular wound shape; more concrete and common for everyday objects like ropes or wires.

  • corkscrew

    Describes a tight, tapering helix; more informal and visual, often referring to a bottle-opening tool.

Grammar Patterns

a [adjective] helix

helix of [noun]

Usage Note

In everyday language, helix and spiral are sometimes used to mean the same thing, but strictly speaking a helix is three-dimensional while a spiral lies in a single plane.

Common Mistakes

The snail shell has a helix shape.
The snail shell has a spiral shape.
Snail shells expand outward in a flat curve (a spiral), not around a fixed central axis (a helix).

2. The curved ridge of cartilage that forms the outer rim of the human ear.

2.nounC1
Definition

The curved ridge of cartilage that forms the outer rim of the human ear.

Example

The doctor gently examined the helix of Noor's ear during the check-up.

anatomical usage: helix of [possessive] ear

The helix of Antonia's left ear was red and slightly swollen after she slept on it.

Common collocations
  • helix piercing
  • helix of the ear
  • outer helix
Synonyms
  • ear rim

    Everyday equivalent for the anatomical term helix; less precise but more widely understood.

Grammar Patterns

the helix of [possessive] ear

[possessive] helix

Usage Note

This is a specialist anatomical term. In everyday conversation, speakers usually say 'the outer rim of the ear' rather than using the word helix.

Common Mistakes

The helix is the soft part at the bottom of the ear.
The helix is the curved rim at the top of the outer ear.
The soft lower part is the earlobe; the helix is the cartilaginous upper rim.

Word family

  • helical
    adjectiveC1
  • helices
    noun (plural)C1
  • helically
    adverbC1

Synonym discussion

Sense: noun/1

Spiral, coil, corkscrew, and helix all describe curved or winding shapes, but with important differences. A spiral is a flat, two-dimensional curve that moves outward from a centre point — like a snail shell or a rope lying on the ground. A helix, by contrast, rises through three dimensions around a central axis, like a spring or a DNA strand. Coil emphasises the act of winding something into circular loops (a coil of rope or wire), while corkscrew suggests a tight, tapering spiral with a pointed end, like the tool used for opening wine bottles. In everyday speech, people often call a helix a 'spiral', but in mathematics and science the distinction matters for accuracy.

spiral ↗coil ↗corkscrew

Common collocations

Nouns

  • double helix
  • helix shape

Phrases

  • form a helix
  • twist into a helix

Prepositions

  • in a helix
  • into a helix

Etymology

GreekLatinEnglish

From Greek 'helix' (ἕλιξ), meaning 'spiral' or 'twisted object', related to 'helissein' (to turn, to roll, to wind). The word passed into Latin as 'helix' and entered English in the 1500s as a term in geometry. The anatomical sense for the outer rim of the ear was adopted in the 1600s from the same Greek root.