allyunify, join; a partner, friend, or confederate: Canada was our ally in World War II.Not to be confused with:allay ? soften, assuage: lay to rest or lull into a sense of security: She tried to allay her child?s fears.alley ? a passage, a narrow back street: Our garage is off the back alley.alloy ? a lower-quality metal mixed with a more valuable one; to debase, impair, or adulterate; fusion, blend, composite: Coins are often alloys.Abused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embreeal·ly (?-l??, ?l??)v. al·lied, al·ly·ing, al·lies v.tr.1. To place in a friendly association, as by treaty: Italy allied itself with Germany during World War II.2. To unite or connect in a personal relationship, as in friendship or marriage.v.intr. To enter into an alliance: Several tribes allied to fend off the invaders.n. (?l??, ?-l??)pl. al·lies 1. One that is allied with another, especially by treaty: entered the war as an ally of France.2. a. One in helpful association with another: legislators who are allies on most issues. See Synonyms at partner.b. An animal that cooperates with another animal of the same species in an alliance.3. Alliesa. The nations allied against the Central Powers of Europe during World War I. They were Russia, France, Great Britain, and later many others, including the United States.b. The nations, primarily Great Britain, France, the Soviet Union, and the United States, allied against the Axis during World War II.[Middle English allien, from Old French alier, from Latin allig?re, to bind to; see alloy.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.ally vb, -lies, -lying or -lied1. to unite or be united, esp formally, as by treaty, confederation, or marriage2. (tr; usually passive) to connect or be related, as through being similar or compatible n, pl -lies3. a country, person, or group allied with another4. (Biology) a plant, animal, substance, etc, closely related to another in characteristics or form [C14: from Old French alier to join, from Latin allig?re to bind to, from lig?re to bind]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014al?ly (n. ?æl a?, ??la?; v. ??la?) n., pl. -lies, n. 1. a nation, group, or person that is associated with another or others for some common cause or purpose: Canada and the United States were allies in World War II. 2. a plant, animal, or other organism bearing a close taxonomic relationship to another. 3. a person who associates or cooperates with another; supporter. v.t. 4. to unite formally, as by treaty, league, or marriage (usu. fol. by with or to): Russia allied itself to France. 5. to associate or connect by some mutual relationship. v.i. 6. to enter into an alliance; unite. [1250?1300;