mid-14c., navie, "fleet of ships," especially for purposes of war, from Old French navie "fleet; ship," from Latin navigia, plural of navigium "vessel, boat," from navis "ship," from PIE root *nau- "boat."
Meaning "a nation's collective, organized sea power" is from 1530s. The Old English words were sciphere (usually of Viking invaders) and scipfierd (usually of the home defenses). Navy blue was the color of the British naval uniform. Navy bean attested from 1856, so called because they were grown to be used by the Navy. Navy-yard "government dockyard," in the U.S. "a dockyard where government ships are built or repaired" is by 1842.
measure of length, Old English gerd (Mercian), gierd (West Saxon) "rod, staff, stick; measure of length," from West Germanic *gazdijo, from Proto-Germanic *gazdjo "stick, rod" (source also of Old Saxon gerda, Old Frisian ierde, Dutch gard "rod;" Old High German garta, German gerte "switch, twig," Old Norse gaddr "spike, sting, nail"), from PIE root *ghazdh-o- "rod, staff, pole" (source also of Latin hasta "shaft, staff"). The nautical yard-arm retains the original sense of "stick."
Originally in Anglo-Saxon times a land measure of roughly 5 meters (a length later called rod, pole, or perch). Modern measure of "three feet" is attested from late 14c. (earlier rough equivalent was the ell of 45 inches, and the verge). In Middle English and after, the word also was a euphemism for "penis" (as in "Love's Labour's Lost," V.ii.676). Slang meaning "one hundred dollars" first attested 1926, American English. Middle English yerd (Old English gierd) also was "yard-land, yard of land," a varying measure but often about 30 acres or a quarter of a hide.
"patch of ground around a house," Old English geard "fenced enclosure, garden, court; residence, house," from Proto-Germanic *gardan- (source also of Old Norse garðr "enclosure, garden, yard;" Old Frisian garda, Dutch gaard, Old High German garto, German Garten "garden;" Gothic gards "house," garda "stall"), of uncertain origin, perhaps from PIE *ghor-to-, suffixed form of root *gher- (1) "to grasp, enclose," with derivatives meaning "enclosure."
As "college campus enclosed by the main buildings," 1630s. Shipyard is from c. 1700. In railway usage, "ground adjacent to a train station or terminus, used for switching or coupling trains," 1827. Yard sale is attested by 1976.
used for "London Metropolitan Police," 1864, from the name of short street off Whitehall, where from 1829 to 1890 stood the headquarters of the Metropolitan Police Force, hence, the force itself, especially the detective branch. After 1890, it was located in "New Scotland Yard."