embattle (v.)

word-forming element meaning "in; into," from French and Old French en-, from Latin in- "in, into" (from PIE root *en "in"). Typically assimilated before -p-, -b-, -m-, -l-, and -r-. Latin in- became en- in French, Spanish, Portuguese, but remained in- in Italian.

Also used with native and imported elements to form verbs from nouns and adjectives, with a sense "put in or on" (encircle), also "cause to be, make into" (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as ensure/insure, and most en- words in English had at one time or another a variant in in-, and vice versa.

"fight or hostile engagement between opposing forces," c. 1300, from Old French bataille "battle, single combat," also "inner turmoil, harsh circumstances; army, body of soldiers," from Late Latin battualia "exercise of soldiers and gladiators in fighting and fencing," from Latin battuere "to beat, to strike" (see batter (v.)).

Battle-cry is from 1812; battle-flagfrom 1840; battle-scarred is from 1848. Phrase battle royal "fight involving several combatants" is from 1670s.

"under attack," by 1882; earlier and more etymologically it meant "prepared to fight" (late 15c.), and (of structures) "fitted with battlements" (late 14c.); past-participle adjective from embattle (v.).