Ally
Middle English (as a verb): from Old French alier, from Latin alligare ‘bind together’, from ad- ‘to’ + ligare ‘to bind’; the noun is partly via Old French alie ‘allied’. Compare with alloy.
wiktionary
From Middle English allien, alien, from Old French alier (Modern Old French allier), from Latin alligō(“to bind to”), from ad(“to”) + ligō(“to bind”). Compare alligate, allay, alloy and ligament.
Diminutive of alabaster.
etymonline
ally (v.)
late 13c., "to join in marriage" (transitive), from Old French alier "combine, unite," from a differentiated stem of aliier (from Latin alligare "bind to, tie to," from ad "to" (see ad-) + ligare "to bind, bind one thing to another, tie" (from PIE root *leig- "to tie, bind"). Meaning "to form an alliance, join, associate" is late 14c. Related: allied; allying.
ally (n.)
late 14c., "relative, kinsman" (a sense now obsolete), from ally (v.); mid-15c. in the sense of "one united with another by treaty or league." Allies as the name of the nations aligned against the Central Powers in World War I is from 1914; as the nations aligned against Germany, Italy and Japan in World War II, from 1939.
