"of or pertaining to a ship or ships," specifically "pertaining to a navy," early 15c., from Old French naval (14c.) and directly from Latin navalis "pertaining to a ship or ships," from navis "ship," from PIE root *nau- "boat." An Old English word for "naval" was scipherelic.
mid-15c., "action of installing," in reference to church offices or other positions, from Medieval Latin installationem (nominative installatio), noun of action from past participle stem of installare (see install). Of machinery, etc., "act of setting up, a placing in position for use," from 1882.
type of cast-iron smooth-bore naval artillery cannon, by 1854, named for its inventor, U.S. naval ordnance officer John A. Dahlgren (1809-1870), who was of Swedish ancestry.
"Finnish steam bath," also the house or room where it is taken, 1881, from Finnish sauna. Originally in a Finnish context; by 1959 in reference to installation in homes and gyms outside Finland.
1660s, "empower or authorize by commission," from commission (n.). In the naval sense, of persons, "be given the rank of an officer (by commission from authority)," from 1793; of a ship, "to be transferred from the naval yard and placed in the command of the officer put in charge of it," 1796. Related: Commissioned; commissioning.
"naval branch of the English executive," early 15c., admiralte, from Old French amiralte, from amirail (see admiral).
"crazy," 1957, British slang, perhaps from earlier naval slang meaning "slightly drunk" (1948), from notion of a thump ("bonk") on the head.
"action of disarming," by 1795; see noun of action from disarm. Especially in reference to reduction of military and naval forces from a war to a peace footing.