protractor

noun

pro·​trac·​tor prō-ˈtrak-tər 

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

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

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

Rhymes for protractor

• attractor
• cofactor
• compactor
• contactor
• contractor
• distractor
• extractor
• impactor
• reactor
• redactor
• refractor
• retractor

Kids Definition

protractor

noun

pro·​trac·​tor prō-ˈtrak-tər 

: an instrument for drawing and measuring angles

Medical Definition

protractor

noun

pro·​trac·​tor -tər 

: a muscle that extends a part compare retractor sense b