"stables grouped around an open yard," 1630s, from Mewes, name of the royal stables at Charing Cross, built 1534 on the site of the former royal mews (attested from late 14c.), where the king's hawks were kept (see mew (n.2)). Extended by 1630s to "an alley or court in a large town on which stables are situated" and by 1805 to "street of former stables converted to human habitations."
It forms all or part of: amiss; amoeba; azimuth; common; commune; communicate; communication; communism; commute; congee; demean; emigrate; emigration; excommunicate; excommunication; immune; immutable; incommunicado; mad; mean (adj.1) "low-quality;" mew (n.2) "cage;" mews; migrate; migration; mis- (1) "bad, wrong;" mistake; Mithras; molt; Mstislav; municipal; munificent; mutable; mutant; mutate; mutation; mutatis mutandis; mutual; permeable; permeate; permutation; permute; remunerate; remuneration; transmutation; transmute; zenith.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit methati "changes, alternates, joins, meets;" Avestan mitho "perverted, false;" Hittite mutai- "be changed into;" Latin mutare "to change," meare "to go, pass," migrare "to move from one place to another," mutuus "done in exchange;" Old Church Slavonic mite "alternately;" Czech mijim "to go by, pass by," Polish mijać "avoid;" Gothic maidjan "to change."
mid-14c., "passage in a house; open passage between buildings; walkway in a garden," from Old French alee (13c., Modern French allée) "a path, passage, way, corridor," also "a going," from fem. of ale, past participle of aler "to go," which is of uncertain origin. It might be a contraction of Latin ambulare "to walk" (Watkins, see amble (v.)), or it might be from Gallo-Roman allari, a back-formation from Latin allatus "having been brought to" [Barnhart]. Compare sense evolution of gate.
Applied by c. 1500 to "long narrow enclosure for playing at bowls, skittles, etc." Used in place names from c. 1500. "In U.S. applied to what in London is called a Mews" [OED], and in American English especially of a back-lane parallel to a main street (1729). To be up someone's alley "in someone's neighborhood" (literally or figuratively) is from 1931; alley-cat (n.) is attested by 1890.