Definition of protractor in English:


Syllabification: pro·trac·tor
Pronunciation: /ˌprōˈtraktər


  • 1An instrument for measuring angles, typically in the form of a flat semicircle marked with degrees along the curved edge.
    More example sentences
    • Do you need a protractor to measure their angles?
    • The angle of pinnation was found by placing a protractor along the central tendon and measuring the angle of an individual fiber to the nearest 0.5 degree.
    • A protractor was used to measure the angle of this line to the transverse line and hence the angle to the apex of the nucellus.
  • 2 (also protractor muscle) chiefly Zoology A muscle serving to extend a part of the body. Compare with retractor.
    More example sentences
    • They accomplish this coordination with proprioceptive feedback through the hypoglossal nerve that disinhibits activation of the jaw depressors when the tongue protractor muscle is activated.
    • Two pairs of epibranchials are present in adults, one bony and one cartilaginous, compared to a single pair in most other families, and the protractor muscle encompasses both epibranchials.
    • In the overhead thrower, the shoulder external rotator muscles, scapular retractor muscles, and protractor and depressor muscles are frequently isolated because of weakness.

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Pronunciation: ˌkɒlərəˈtjʊərə
elaborate ornamentation of a vocal melody