ally

Etymology 1

From Middle English allien, alien (“to form an alliance, associate, join; to become an ally; to introduce (someone) as an ally; to marry; to become related (to someone); to attack, engage in combat; to combine; (cooking) to combine ingredients, especially to bind them together”) [and other forms], from Anglo-Norman alier, allier, Middle French alier, allier [and other forms], and Old French alier (“to join together, unite; to alloy (metals); (cooking) to combine ingredients”) (modern French allier), from Latin alligāre, the present active infinitive of alligō, adligō (“to bind around, to, or up (something), bandage, fasten, fetter, tie; to hold fast; to detain, hinder”), from al-, ad- (intensifying prefix) + ligō (“to bind, tie; to bandage, wrap around; to unite”) (from Proto-Indo-European *leyǵ- (“to bind, tie”)). Doublet of allay, alligate, alloy, and ligament.

verb

1. (transitive)
   1. To unite or form a connection between (people or things), as between families by marriage, or between states by confederacy, league, or treaty.
      Solomon preferreth her Pharaoh's daughter] before the reſt of his vvives, for they vvere of Nations that vvere his Subjects, but ſhe the daughter of an intire King, and by this match he allieth that potent King to him, and ſecureth himſelf the better abroad; […] 1634, John Lightfoot, “A Chronicle of the Times, and the Order of the Texts of the Old Testament. The First Book of Kings.]”, in George Bright, editor, The Works of the Reverend and Learned John Lightfoot D.D.[…], London: […] W[illiam] R[awlins] for Robert Scot[…], Thomas Basset[…], Richard Chiswell[…], and John Wright[…], →OCLC, page 73
   2. Chiefly followed by to or with: to connect or form a relation to (someone or something) by similarity in features or nature.
   3. (reflexive) To join or unite (oneself or itself) against, with, etc., someone or something else.
      To be ſhort, hauing thus ingrafted them into the body of his [God's] Sonne, he ioyneth and allieth him ſelfe to them, he maketh him ſelfe one with them, maketh them his children and heyres, partakers of his immortalitie and glorie, and all this he worketh by the inward vertue of his holy Ghost, […] 1577, Peter de la Place [i.e. Pierre de la Place], “Of the Excellencie of a Christian Man, and the Way to Knowe Him”, in L[aurence] Tomson, transl., A Treatise of the Excellencie of a Christian Man, and Howe He may be Knowen.[…], London: […] Christopher Barkar,[…], →OCLC
      And do we upbraid thee [rain], in our heartless stupidity, because, rather than withhold thy life-giving dispensations, thou allyest thy gentle nature with thy opposites, and comest in unwelcome company—in chilly league with Eurus, or riding on the stormy wings of night-confounding Aquilo— […] 1841, W[illia]m H. Simmons, “Rain. A Colloquial Lecture.”, in George Stillman Hillard], editor, The Boston Book. Being Specimens of Metropolitan Literature, Boston, Mass.: George W. Light,[…], →OCLC, page 306
      A wise damsel walketh up and down discreetly in the world, minding her affairs: she regardeth not the pleading of vain lovers, but taketh counsel with her friends and allieth herself at last to one of true worth. Then she giveth up her whole heart to the service of her husband, and receiveth from him again his love and strong help and the flower of his estate beyond calcuation or desire. 1861, [T. John Vickers], “The Book of Counsels”, in The New Koran of the Pacifican Friendhood: or Text-book of Turkish Reformers, in the Teaching and Example of Their Esteemed Master Jaido Morata, London: George Mainwaring,[…], →OCLC, chapter XXIX, verses 24–25, page 375, column 1
      Poor Poverty! […] Well art thou in the right when thou alliest thyself to Vice and Crime. 1887, Heinrich Heine, “English Fragments. London.”, in Mr. Leland, transl., edited by Havelock Ellis, The Prose Writings of Heinrich Heine:[…] (The Camelot Series), London: Walter Scott[…], →OCLC, page 51
2. (intransitive) Chiefly followed by with: to enter into an alliance or unite for a common aim.

Etymology 2

From Middle English allie, alie [and other forms], probably partly: * from allien (verb): see etymology 1; and * from Anglo-Norman allié, alié, alyé, allyé, Middle French allié, alié, allyé (“associate, supporter; friend; relative; person, state, etc., associated or united with another by alliance or treaty”), and Old French alliiet (“military or political ally”) (modern French allié), a noun use of the past participle of Anglo-Norman alier, allier, Middle French alier, allier, and Old French alier (verb): see etymology 1.

noun

1. A person who co-operates with or helps another; an associate; a friend.
   1. A person who, or organization which, supports a demographic group subject to discrimination and/or misrepresentation but is not a member of the group; specifically (LGBT), a person who is not a member of the LGBT+ community but is supportive of it.
      I’m glad you want to be a better ally to the disabled.
2. A person, group, state, etc., which is associated or united by treaty with another for a common (especially military or political) purpose; a confederate.
   The two countries were allies in World War I.
   Even before she begs Jon to keep his identity a secret, she reeks of desperation; in order to gain an ally that isn’t already in her entourage, she sets Gendry Baratheon né Rivers up in Storm’s End. 5 May 2019, Danette Chavez, “Campaigns are Waged On and Off the Game Of Thrones Battlefield (Newbies)”, in The A.V. Club, archived from the original on 2021-01-28
3. Something regarded as connected with or related to another thing by similarity in features or nature.
   1. (taxonomy) An organism which is related to another organism through common evolutionary origin; specifically, a species which is closely related to another species, usually within the same family.
      The order of Gruiformes includes cranes and their allies.
      Procyonids (raccoons and their allies), a group of North American origin, are first recorded in South America in a level immediately below a unit dated at 6.0 million years. 1979, Larry G. Marshall et al., “Calibration of the Great American Interchange: A radioisotope chronology for Late Tertiary interchange of terrestrial faunas between the Americas.”, in Science, volume 204, number 4390, →DOI, pages 272–279
4. (figurative) A person, group, concept, etc., which is associated with another as a helper; an auxiliary; a supporter.
   [S]cience, instead of being the enemy of religion, becomes its ally. 1861, Henry Thomas Buckle, “An Examination of the Scotch Intellect during the Eighteenth Century”, in History of Civilization in England, volume II, London: Parker, Son, and Bourn,[…], →OCLC, page 596
5. (historical or obsolete) A kinsman or kinswoman; a relative.

noun

1. One's relatives; kin, kindred, relations; also, relationship through descent or marriage; kinship.
2. People, groups, states, etc., which are associated or united with each other for a common purpose; confederates; also, the state of being allied; alliance, confederation.

Etymology 3

See alley.

noun

1. Alternative spelling of alley (“a glass marble or taw”)