protractor

noun

pro·​trac·​tor prō-ˈtrak-tər How to pronounce protractor (audio)
prə-
1
a
: one that protracts
b
: a muscle that extends a part
2
: an instrument for laying down and measuring angles in drawing and plotting

Examples of protractor in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
At his best, Towns shoots like an archer, drives to the hoop like a rugby bruiser, and glides on his pivot foot, one smooth semicircle after another, like a grade-school protractor with its point puncturing the paper. —Vinson Cunningham, New Yorker, 2 June 2025 Your protractor: don’t leave home in a zombie apocalypse without it! —Sara Netzley, EW.com, 12 May 2025 Matt Futterman Shot of the week Coco Gauff has tennis fans digging out their protractors with this one. —Charlie Eccleshare, The Athletic, 6 Jan. 2025 This useful multitool fits on any keychain but has a staggering 16 different functions, including screw driver, protractor, ruler, bottle opener, and bike spoke key. —Malia Griggs, Glamour, 11 Oct. 2024 See All Example Sentences for protractor

Word History

Etymology

probably borrowed from Medieval Latin prōtractor "instrument for measuring angles," from Latin prōtrac-, variant stem of prōtrahere "to drag forward, draw or pull out, bring into the open" + -tor, agent suffix — more at protract

Note: The word occurs at least once in printed versions of the Peri optikēs (known as the Perspectiva) of Vitellio/Witelo, the first of which appeared in Nuremberg in 1535. Witelo, taken to be ethnically Polish, was a natural scientist and philosopher born in Silesia in the thirteenth century.

First Known Use

1588, in the meaning defined at sense 2

Time Traveler
The first known use of protractor was in 1588

Rhymes for protractor

See All Rhymes for protractor

Browse Nearby Words

protraction
protractor
Protremata
See all Nearby Words

Cite this Entry

“Protractor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/protractor. Accessed 31 Oct. 2025.

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Kids Definition

protractor

noun
pro·​trac·​tor prō-ˈtrak-tər How to pronounce protractor (audio)
: an instrument for drawing and measuring angles

Medical Definition

protractor

noun
pro·​trac·​tor -tər How to pronounce protractor (audio)
: a muscle that extends a part compare retractor sense b

More from Merriam-Webster on protractor

Nglish: Translation of protractor for Spanish Speakers

Britannica.com: Encyclopedia article about protractor

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