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

The state is no longer collecting sales tax on nonelectronic school supplies, which includes a long list of items like paper, notebooks, binder, pens, pencils and markers, rules and protractors, glue, highlighters, index cards and scissors. — Staff Report, Hartford Courant, 15 Aug. 2026

Cropping and Noise Reduction The Crop tool includes straightening with an on-screen protractor for angle measurement. — Michael Muchmore, PC Magazine, 29 June 2026

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

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

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