from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A thick triangular muscle covering the shoulder joint, used to raise the arm from the side.
  • adj. Triangular.
  • adj. Of or relating to the deltoid.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The deltoid muscle, a triangular muscle on the human shoulder.
  • n. The deltoid ligament, a triangular ligament on the human ankle.
  • adj. In the shape of the upper case Greek letter delta Δ; triangular.
  • adj. Of, or connected with the deltoid muscle
  • adj. Of a triangular or roughly triangular shape and attached to the stem via the side.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Shaped like the Greek Δ (delta); delta-shaped; triangular.
  • adj. of or pertaining to the deltoid muscle.
  • n. the deltoid muscle.

from The Century Dictionary and Cyclopedia

  • Resembling the Greek letter Δ; triangular.
  • Specifically— In anatomy:
  • Forming a triangular place or part; being triangular: as, the deltoid muscle.
  • Relating to the deltoid muscle: as, the deltoid crest of the humerus.
  • In entomology, pertaining to or resembling the pyralid moths, or Deltoides.
  • In botany, triangular or trowel-shaped: as, a deltoid leaf: also applied to the cross-section of a leaf, etc.
  • n. The large, coarse-fibered, triangular muscle of the shoulder, covering and protecting the joint, arising from the spine of the scapula, the acromion, and the clavicle, and inserted into the deltoid crest of the humerus. Its action raises the arm away from the side of the body. See cut under muscle.
  • n. In zoology, a deltoid plate.
  • n. In mathematics, a symmetrical quadrilateral with a diagonal as axis.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. triangular or suggesting a capital delta, with a point at the apex
  • n. a large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm


from The American Heritage® Dictionary of the English Language, 4th Edition

New Latin deltoīdēs, from Greek deltoeidēs, triangular : delta, delta; see delta + -oeidēs, -oid.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From deltoideus, which was in turn from Ancient Greek adjective δελτοειδής. See also: δέλτα (delta) the fourth letter of the Greek alphabet.


  • They would aim for the muscle that Tariq, in a professorial voice, called the deltoid

    A Thousand Splendid Suns

  • To the nullah I observed Stellaria cana, Berberis asiatica, which has re - appeared, Erythrina, Rubus deltoid, which is very common all over these parts and whose fruit is palatable, Uvularia, Swertia plantaginifolia,

    Journals of Travels in Assam, Burma, Bhootan, Afghanistan and the Neighbouring Countries

  • -- The deltoid is the simplest, and the most easily constructed of all the kites.


  • Thus, though Guthrie believed that the insertion of the deltoid was the lowest point at which the bone should be divided, Esmarch has shown that at least four and a half inches can be removed and yet a most useful arm remain.

    An Epitome of Practical Surgery, for Field and Hospital.

  • The researchers used embryonic mouse skeletons to study a bone ridge called the deltoid tuberosity, located on the humerus bone in the arm.

    EurekAlert! - Breaking News

  • Its leaf is 'deltoid' in shape and indented at the edge.

    Among the Trees at Elmridge

  • I get Drug Monkey, Tim "deltoid" Lambert, Pal MD?,

    ScienceBlogs Channel : Life Science

  • Dante drew in a breath, then contracted his deltoid muscles.

    Etched in Bone

  • He flexed his shoulder and deltoid muscles, then black wings slid out from beneath his white skin in a rush and unfurled, snapping the scent of burning leaves and musk into the air.

    Etched in Bone

  • He arrowed himself down toward the yacht, dropping from eight stories above the white-capped water to five, his deltoid muscles burning as his wings slashed through the humid air, the salt tang of brine prickling his nostrils.

    Etched in Bone


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