1801, from tight (adj.) + rope (n.). So called for being tensely stretched.
Entries linking to tightrope
tight adj.
c. 1400, tyght "dense, close, compact," from Middle English thight, from Old Norse þettr "watertight, close in texture, solid," and also from Old English -þiht (compare second element in meteþiht "stout from eating"), both from Proto-Germanic *thinhta- (source also of Middle High German dihte "dense, thick," German dicht "dense, tight," Old High German gidigan, German gediegen "genuine, solid, worthy"), from PIE root *tenk- (2) "to become firm, curdle, thicken" (source also of Irish techt "curdled, coagulated," Lithuanian tankus "close, tight," Persian tang "tight," Sanskrit tanakti "draws together, contracts").
Sense of "drawn, stretched" is from 1570s; meaning "fitting closely" (as of garments) is from 1779; that of "evenly matched" (of a contest, bargain, etc.) is from 1828, American English; that of "drunk" is from 1830. Of persons, "close, intimate, sympathetic" from 1956. From 1670s as an adverb; to sit tight is from 1738; sleep tight as a farewell in sending someone off to bed is by 1871. Related: Tightly; tightness. Tight-assed "unwilling to relax" is attested from 1903. Tight-laced is recorded from 1741 in both the literal and figurative senses. Tight-lipped is first attested 1872.
rope n.
Middle English rop, from Old English rap "strong, heavy cord of considerable thickness," from Proto-Germanic *raipaz (source also of Old Norse reip, West Frisian reap, Middle Dutch, Dutch reep "rope," Old Frisian silrap "shoe-thong," Gothic skauda-raip "shoe-lace," Old High German, German reif "ring, hoop"). Technically, only cordage above one inch in circumference and below 10 (bigger-around than that is a cable). Nautical use varies. Finnish raippa "hoop, rope, twig" is a Germanic loan-word.
It is attested by early 14c. as "a noose, a snare." Rope of sand (1620s) was an old figure for anything lacking coherence or binding power.
To know the ropes "understand the way to do something" (1840, Dana) originally was a seaman's term. The phrase on the ropes "about to be defeated" is attested from 1924, a figurative extension from the fight ring, where being in or on the ropes was a figure by 1829.
To be at the end of (one's) rope "out of resources and options" is attested by 1680s. An earlier expression was have too long rope "have too much freedom" (late 15c.).
Rope formerly also figured in slang and extended-sense expressions related to punishment by hanging, such as John Roper's window "a noose," rope-ripe "deserving to be hanged," both 16c. The figurative phrase give someone (enough) rope (to hang himself) is by 1680s.