early 13c., pouren, "gaze intently, look with close and steady attention or examination," a word of unknown origin, with no obvious corresponding word in Old French. Perhaps from an unrecorded Old English *purian, suggested by spyrian "to investigate, examine" (cognate with Old Norse spyrja) and spor "a trace, vestige." Especially, but not originally, "to read something with steady perseverance" (late 14c.), with on or over. Related: Pored; poring.
past participle of do (v.); from Old English past participle gedon (a vestige of the prefix is in ado). As a past-participle adjective meaning "completed, finished, performed, accomplished" from early 15c. As a word of acceptance of a deal or wager, 1590s.
U.S. Southern use of done in phrases such as done gone (or "Octopots done got Albert!") is attested by 1827, according to OED: "a perfective auxiliary or with adverbial force in the sense 'already; completely.' " Century Dictionary writes that it was "originally causal after have or had, followed by an object infinitive ; in present use the have or had is often omitted and the infinitive turned into a preterit, leaving done as a mere preterit sign" and calls it "a characteristic of negro idiom."
To be done in "exhausted" is by 1917. Slang done for "doomed" is by 1803 (colloquial do for "ruin, damage" is from 1740). To have done it "to have been very foolish, made a mess of things" is from 1837.
"agreement in terminal sounds of words or metrical lines," a 16c. attempt to restore a classical spelling to Middle English ryme, rime (c. 1200) "measure, meter, rhythm," later "rhymed verse" (mid-13c.), from Old French rime (fem.), which is related to Old Provençal rim (masc.), earlier *ritme, from Latin rithmus, from Greek rhythmos "measured flow or movement, rhythm; proportion, symmetry; arrangement, order; form, shape, wise, manner; soul, disposition," related to rhein "to flow" (from PIE root *sreu- "to flow").
The persistence of rime, the older form of the word, perhaps is due to popular association with Old English rim "number" (from PIE root *re- "to reason, count"). The intermediate form rhime was frequent until late 18c.
In Medieval Latin, rithmus was used for accentual, as opposed to quantitative, verse, and accentual verse usually was rhymed, hence the sense shift. In prosody, specifically the quality of agreement in end-sounds such that the last stressed vowel, and any sounds after it, are the same, and preceding sounds differ.
Verse was invented as an aid to memory. Later it was preserved to increase pleasure by the spectacle of difficulty overcome. That it should still survive in dramatic art is a vestige of barbarism. [Stendhal "de l'Amour," 1822]
The sense of "a piece of poetry in which consonance of end-sounds is observed" is from 1610s. From 1650s as "word that rhymes with another." The phrase rhyme or reason "good sense" (chiefly used in the negative) is from late 15c. (see reason (n.)). Rhyme scheme "ordered pattern of end-rhymes in metrical composition" is attested from 1931. Rhyme royal (1841) is a stanza of seven 10-syllable lines rhymed a-b-a-b-b-c-c.