torus

noun

to·​rus ˈtȯr-əs 

plural tori ˈtȯr-ˌī  -ˌē 

1

: a large molding of convex profile commonly occurring as the lowest molding in the base of a column

2

: the thickening of a membrane closing a wood-cell pit (as of gymnosperm tracheids) having the secondary cell wall arched over the pit cavity

3

: a doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle

broadly : toroid

4

: a smooth rounded anatomical protuberance (such as a bony ridge on the skull)

Examples of torus in a Sentence

Recent Examples on the Web

At lower angles still, the dust torus starts to the block the highest-energy light from reaching us. —Phil Plait, Scientific American, 16 Oct. 2025

Twisted Mysteries The counterexample Brittenham and Hermiller found is built out of two copies of a knot called the (2, 7) torus knot. —Leila Sloman, Quanta Magazine, 22 Sep. 2025

The duo have been cautious in their classification, allowing for the possibility that a torus of material could be behind the observations. —Nola Taylor Tillman, Space.com, 10 Sep. 2025

Ejecta from its innermost large, volcano-rich moon, Io, populates this inner magnetosphere with sulfur dioxide gas, where the magnetic field forces this material to co-rotate with Jupiter itself in a torus-like shape. —Ethan Siegel, Big Think, 3 Sep. 2025

Word History

Etymology

New Latin, from Latin, protuberance, bulge, torus molding

First Known Use

1563, in the meaning defined at sense 1

Rhymes for torus

• chloris
• chorus
• horus
• lores
• morrice
• morus
• orris
• porous
• porus
• authorise
• clitoris
• liquorice

Medical Definition

torus

noun

to·​rus ˈtōr-əs, ˈtȯr- 

plural tori ˈtō(ə)r-ˌī  ˈtȯ(ə)r- 

-ˌē

1

: a doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle

2

: a smooth rounded anatomical protuberance (as a bony ridge on the skull)

a supraorbital torus