1. A thick triangular muscle covering the shoulder joint, used to raise the arm from the side.
2. See kite.
b. Having the shape of a geometric kite.
2. Of or relating to the deltoid.
[New Latin deltoīdēs, from Greek deltoeidēs, triangular : delta, delta; see DELTA + -oeidēs, -oid.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.