1580s, "suitable connection or dependence, consistency" (in narrative or argument), also more literally "act or state of sticking or cleaving of one thing to another," from French cohérence (16c.), from Latin cohaerentia, abstract noun from cohaerentem(nominative cohaerens), present participle of cohaerere "to stick together, be coherent," from assimilated form of com "together" (see co-) + haerere "to adhere, stick" (see hesitation). Related: Coherency.
1590s, "state of standing still; firmness," from French consistence (Modern French consistance) "a standing fast," from Medieval Latin consistentia, literally "a standing together," from Latin consistentem (nominative consistens), present participle of consistere "to stand firm, take a standing position, stop, halt," from assimilated form of com "with, together" (see con-) + sistere "to place," causative of stare "to stand, be standing" (from PIE root *sta- "to stand, make or be firm"). Meaning "coherence, solidity, state or degree of density" is recorded from 1620s.
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.