verb

• (transitive)
  "Theſe three did loue each other dearely well, / And with ſo firme affection were allyde, / As if but one ſoule in them all did dvvell, / VVhich did her povvre into three parts diuyde; […]"
• (transitive)
  "Yes in good ſooth, the vice is of a great kindred; it is vvell allied, but it is impoſſible to extirpe it quite, Frier, till eating and drinking be put dovvne."
• (transitive)
  "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, […]"
• (intransitive) Chiefly followed by with: to enter into an alliance or unite for a common aim.
  "[A]ftervvards he [Constantine the Great] allied vvith Licinius, and gave him his Siſter in marriage, and acknovvledged him his Colleague in the Empire."

noun

• Something regarded as connected with or related to another thing by similarity in features or nature.
  "The order of Gruiformes includes cranes and their allies."
• (figuratively) 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."
• (historical or obsolete) A kinsman or kinswoman; a relative.
  "This Gentleman the Princes neere Alie. / My very frend hath tane this mortall vvound / In my behalfe, […]"