torus

noun
to·​rus | \ ˈtȯr-əs How to pronounce torus (audio) \
plural tori\ ˈtȯr-​ˌī How to pronounce tori (audio) , -​ˌē \

Definition of torus

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 To see why the local curvature of an arbitrary shape is almost never equal to its average curvature, consider a torus. Spyridon Michalakis, Scientific American, "How Scientists Solved One of the Greatest Open Questions in Quantum Physics," 1 Aug. 2020 Gauss-Bonnet implies that the average curvature of a torus, and of any shape with a single hole in it, is zero. Spyridon Michalakis, Scientific American, "How Scientists Solved One of the Greatest Open Questions in Quantum Physics," 1 Aug. 2020 As Io sweeps by Jupiter, the planet drags particles off its surface, forming a small magnetosphere, or plasma torus around the moon. Jennifer Leman, Popular Mechanics, "Every Moon in Our Solar System, Ranked," 7 Apr. 2020 But a spherical torus like NSTX resembles a cored apple. Adrian Cho, Science | AAAS, "After decades of decline, the U.S. national fusion lab seeks a rebirth," 6 Feb. 2020 String theory and number theory have common ground in a specific kind of elliptic curve from a torus. Caroline Delbert, Popular Mechanics, "String Theory and Number Theory Have More in Common Than You Think, Maaaaaan," 2 Mar. 2020 Moreover, in a spherical torus, several different magnet coils are crammed precariously into the narrow hole. Adrian Cho, Science | AAAS, "After decades of decline, the U.S. national fusion lab seeks a rebirth," 6 Feb. 2020 To trap a plasma, the magnetic field going around the torus must twist like the stripes on a candy cane. Adrian Cho, Science | AAAS, "After decades of decline, the U.S. national fusion lab seeks a rebirth," 6 Feb. 2020 Even farther out, there's a torus of material that's still expanding away from the stars, possibly first ejected when the envelope of the giant star first engulfed its companion. John Timmer, Ars Technica, "Images obtained of two stars in the process of a merger," 5 Feb. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'torus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of torus

1563, in the meaning defined at sense 1

History and Etymology for torus

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

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Time Traveler for torus

Time Traveler

The first known use of torus was in 1563

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Cite this Entry

“Torus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/torus. Accessed 4 Dec. 2020.

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More Definitions for torus

torus

noun
to·​rus | \ ˈtōr-əs, ˈtȯr- How to pronounce torus (audio) \
plural tori\ ˈtō(ə)r-​ˌī How to pronounce tori (audio) , ˈtȯ(ə)r-​ How to pronounce tori (audio) , -​ˌē \

Medical Definition of torus

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

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