empower 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.

c. 1300, pouer, "ability; ability to act or do; strength, vigor, might," especially in battle; "efficacy; control, mastery, lordship, dominion, ability or right to command or control; legal power or authority; authorization; military force, an army," from Anglo-French pouair, Old French povoir, noun use of the infinitive, "to be able," earlier podir (9c.), from Vulgar Latin *potere (source also of Spanish poder, Italian potere), from Latin potis "powerful" (from PIE root *poti- "powerful; lord").

Whatever some hypocritical ministers of government may say about it, power is the greatest of all pleasures. It seems to me that only love can beat it, and love is a happy illness that can't be picked up as easily as a Ministry. [Stendhal "de l'Amour," 1822]

Meaning "one who has power, person in authority or exercising great influence in a community" is late 14c. Meaning "a specific ability or capacity" is from early 15c. In mechanics, "that with which work can be done," by 1727.

Sense of "property of an inanimate thing or agency of modifying other things" is by 1590s. Meaning "a state or nation with regard to international authority or influence" [OED] is from 1726. Meaning "energy available for work is from 1727. Sense of "electrical supply" is from 1896.

Colloquial a power of for "a large quantity of, a great number of" is from 1660s (compare powerful). Phrase the powers that be "the authorities concerned" is from Romans xiii.1. As a statement wishing good luck, more power to(someone) is recorded from 1842. A man-advantage power play in ice hockey so called by 1940. Power failure "failure of the (electrical) power supply" is from 1911; power steering in a motor vehicle is from 1921. Power politics "political action based on or backed by threats of force" (1937) translates German Macht-politik.