• synonyms


See more synonyms for deltoid on Thesaurus.com
  1. Anatomy. a large, triangular muscle covering the joint of the shoulder, the action of which raises the arm away from the side of the body.
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  1. Anatomy. pertaining to or involving the deltoid.
  2. Also deltoidal. in the shape of a Greek capital delta (Δ); triangular.
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Origin of deltoid

1675–85; < Greek deltoeidḗs delta-shaped, equivalent to délt(a) delta + -oeidēs -oid
Related formssub·del·toid, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for deltoid

trilateral, cuneate, deltoid, deltoidal, hastate, pyramidal, pyriform, trigonal

Examples from the Web for deltoid

Historical Examples of deltoid

  • A red dab over the sternum, and on each arm in front of the deltoid.

    Castes and Tribes of Southern India

    Edgar Thurston

  • (1-2 inches) long; leaves narrowly ovate to deltoid, 2.5-6 cm.

    Trees of Indiana

    Charles Clemon Deam

  • He told her what Sopley had said about his deltoid, Henson about his thigh.

    The Story of Louie

    Oliver Onions

  • What has become of the other two, the sterno-cleido mastoid and the deltoid?

  • The portion of this muscle which is next the scapula is covered by the deltoid.

British Dictionary definitions for deltoid


  1. the thick muscle forming the rounded contour of the outer edge of the shoulder and acting to raise the arm
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  1. shaped like a Greek capital delta, Δ; triangular
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Word Origin for deltoid

C18: from Greek deltoeidēs triangular, from delta
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

Word Origin and History for deltoid


1741, in deltoid muscle, so called for its shape, from Greek deltoeides "triangular," literally "shaped like the letter delta;" see delta + -oid.

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Online Etymology Dictionary, © 2010 Douglas Harper

deltoid in Medicine


  1. Of or relating to the deltoid muscle.
  2. Triangular in shape or outline.
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  1. The deltoid muscle.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.