a. A close association of nations or other groups, formed to advance common interests or causes: an alliance of labor unions opposing the bill.
b. A formal agreement establishing such an association, especially an international treaty of friendship.
a. A connection based on kinship, marriage, or common interest; a bond or tie: the shifting alliances within a large family.
b. A long-term association of two or more animals of the same species, in which members cooperate for a purpose such as gaining access to mates or defending territory.
3. Close similarity in nature or type; affinity: the ancient alliance between mathematics and music.
4. The act of becoming allied or the condition of being allied: the church, acting in alliance with community groups.
[Middle English, from Old French aliance, from alier, to ally; see ALLY.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.