n. pl. ar·mies
a. A large body of people organized and trained for land warfare.
b. often Army The entire military land forces of a country.
c. A tactical and administrative military unit consisting of a headquarters, two or more corps, and auxiliary forces.
2. A large group of people or things, especially when organized for a specific cause or purpose: the construction army that built the Panama Canal; a banquet with an army of waiters. See Synonyms at multitude.
[Middle English armee, from Old French, from Medieval Latin armāta, from Latin, feminine past participle of armāre, to arm, from arma, arms; see ar- in the Appendix of Indo-European roots.]
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.