Origin and history of sling

c. 1300, "hand-held implement for throwing stones" (consisting of a strap and two strings), from an unidentified continental Germanic source (such as Middle Low German slinge "a sling") from verbs meaning "swing to and fro, wind, twist" (see sling (v.1)).

The notion probably is of being twisted and twirled before it is released. The piece of stone or metal hurled from it is a sling-stone (late 14c.). The older English word for this ancient weapon was lithere (Old English liþere, related to leather).

Some of the sense developments might have been influenced by Low German cognates. The sense of "loop for lifting or carrying heavy objects" is recorded by early 14c. As "leather shoulder strap for a rifle, etc.," by 1711. The meaning "piece of cloth tied in a hanging loop around the neck to support an injured arm" is attested by 1720. A Middle English medical word for "sling or supporting loop used in treating dislocations" was stremb (early 15c., Chauliac, who also has suspensorie), from Medieval Latin stremba. 

The Greeks, Romans, and Carthaginians had bodies of slingers attached to their armies, recruited especially from the inhabitants of the Balearic Isles. The use of the sling continued among European armies to the sixteenth century, at which time it was employed to hurl grenades. [Century Dictionary]

c. 1200, slingen (past tense slong, past participle slungen, slongen), "to knock down" using a sling, later "to throw, hurl, fling" (mid-13c.), especially with a sling, probably from Old Norse slyngva, from Proto-Germanic *slingwanan (source also of Old High German slingan, German schlingen "to swing to and fro, wind, twist;" rare Old English slingan "to creep, twist;" Old Frisian slinge, Middle Dutch slinge, Old High German slinga, German Schlinge "sling;" Middle Swedish slonga "noose, knot, snare"). This is reconstructed to be from PIE *slengwh "to slide, make slide; sling, throw." Related: Slung; slinging.

sweetened, flavored liquor drink, 1792, American English, a word of unknown origin; perhaps from the notion of "throw back" a drink (see sling (v.1)), or from German schlingen "to swallow." In 19c. also a verb, "to drink slings."

"act of throwing, a sweep or swing," 1660s, perhaps 1520s, from sling (v.).

1520s, "place in a sling in order to hoist, move or swing by a rope from which the object is suspended," from sling (n.1). From 1690s in transitive sense of "hang or suspend loosely from one point to another" (as a hammock). Related: Slung; slinging.