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protractor

American  
[proh-trak-ter, pruh-] / proʊˈtræk tər, prə- /

noun

  1. a person or thing that protracts.

  2. (in surveying, mathematics, etc.) an instrument having a graduated arc for plotting or measuring angles.

  3. Anatomy. a muscle that causes a part to protrude.


protractor British  
/ prəˈtræktə /

noun

  1. an instrument for measuring or drawing angles on paper, usually a flat semicircular transparent plastic sheet graduated in degrees

  2. a person or thing that protracts

  3. a surgical instrument for removing a bullet from the body

  4. anatomy a former term for extensor

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of protractor

From Medieval Latin, dating back to 1605–15; protract, -tor

Explanation

A protractor is a device used in drafting and drawing: it's mainly used for drawing and measuring angles. Don't show up to geometry without your protractor! In math class, you use many tools, such as a calculator. Another is the protractor, which is handy when you're studying geometry. Protractors are designed to help you measure and draw angles. You can make a rhombus or an isosceles triangle with a protractor. A protractor can help you measure existing angles too, like if you’re taking a geometry test and need to compare angle measurements. Graphic artists, architects, and other professionals who need to make angles use protractors.

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Vocabulary lists containing protractor

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The head coach gets a warning, I mean that normally - I don’t know, I didn’t have a protractor out there.

From Washington Times • Dec. 11, 2023

Cook admitted he had done his mapping with a protractor and his naked eye, a methodology that seemed to leave Judge Zuniga in disbelief.

From Los Angeles Times • Jun. 29, 2021

Study is holding an open book and is surrounded by objects of learning: a lyre, an artist's palette and a protractor.

From BBC • Oct. 23, 2020

He excelled at math as a kid and especially enjoyed teaching his friends to use a protractor.

From Washington Post • Aug. 29, 2015

Downstairs, I can’t find my protractor, which I need for geometry.

From "Liar & Spy" by Rebecca Stead