Origin and history of tug

"pull with a rope," Middle English touen, "haul or draw (something) by force," from Old English togian "to drag, pull," from Proto-Germanic *tugojanan (source also of Old English teon "to draw," Old Frisian togia "to pull about," Old Norse toga, Old High German zogon, German ziehen "to draw, pull, drag"), from PIE root *deuk- "to lead" (source also of Latin ducere "to lead").

Especially "draw through water by means of a rope or chain" (late 14c., implied in towing); the older general sense became obsolete; the maritime sense was transferred to automobiles. Related: Towed.

1769, "pin passed through the eye of a rope, strap, or bolt to hold it in place," a nautical word of uncertain origin. Perhaps a frequentative form of tog "tug;" compare tuggle (v.), in Middle English also toggle, "pull about roughly; toss about, push and pull," from tug (v.); also compare tow (v.).

As a kind of wall fastener it is recorded from 1934. Toggle bolt, one with a bore through the head for a toggle, is attested from 1794; toggle switch, the up-and-down sort, is attested by 1938. The word is used in electronics by 1953, and in computing by 1979 in reference to a key which alternates the function between on and off when struck.