c. 1500, "of or pertaining to Sappho or her poems," especially in reference to her characteristic meter, from French saphique, from Latin Sapphicus, from Greek Sapphikos "of Sappho," in reference to Sapphō, Greek lyric poetess of the isle of Lesbos who flourished c. 600 B.C.E. and was famed for the passion and loveliness of her verse, which survives mostly in fragments. The sense of "pertaining to sexual relations between women" is from 1890s (also see Sapphism, and compare lesbian).
late 14c., "one of the nine Muses of classical mythology," daughters of Zeus and Mnemosyne, protectors of the arts; from Old French Muse and directly from Latin Musa, from Greek Mousa, "the Muse," also "music, song," ultimately from PIE root *men- (1) "to think." Meaning "inspiring goddess of a particular poet" (with a lower-case m-) is from late 14c.
The traditional names and specialties of the nine Muses are: Calliope (epic poetry), Clio (history), Erato (love poetry, lyric art), Euterpe (music, especially flute), Melpomene (tragedy), Polymnia (hymns), Terpsichore (dance), Thalia (comedy), Urania (astronomy).
"tedious and ineffectual person," 1935, American English carnival slang, of uncertain origin. Perhaps from jerkwater "petty, inferior, insignificant" [Barnhart, OED]; alternatively from, or influenced by, verbal phrase jerk off "masturbate" [Rawson]. The lyric in "Big Rock Candy Mountain," sometimes offered as evidence of earlier use, apparently is "Where they hung the Turk [not jerk] that invented work."
A soda-jerk (1915; soda-jerker is from 1883) is so called for the pulling motion required to work the taps.
The SODA-FOUNTAIN CLERK
Consider now the meek and humble soda-fountain clerk,
Who draweth off the moistened air with nimble turn and jerk,
[etc., Bulletin of Pharmacy, August, 1902]
c. 1300, melodie, "vocal or instrumental music, a succession of agreeable musical sounds," from Old French melodie "music, song, tune" (12c.) and directly from Late Latin melodia "a pleasant song" (in Medieval Latin also "music" generally), from Greek melōidia "a singing, a chanting; a choral song, a tune for lyric poetry," from melos "song, part of song; limb, member" (a word of uncertain origin) + ōidē "song, ode" (see ode). From late 14c. as "a song of clear and balanced form." Sense of "a series of tones so related to one another as to produce a distinct musical phrase or idea, a tune" is by c. 1600. Meaning "the principal voice-part in a harmonic composition" is by 1880.
1557 (in title of Surrey's poems), from French sonnet (1540s) or directly from Italian sonetto, literally "little song," from Old Provençal sonet "song," diminutive of son "song, sound," from Latin sonus "sound" (from PIE root *swen- "to sound").
Originally in English also "any short lyric poem;" precise meaning is from Italian, where Petrarch (14c.) developed a scheme of an eight-line stanza (rhymed abba abba) followed by a six-line stanza (cdecde, the Italian sestet, or cdcdcd, the Sicilian sestet). Shakespeare developed the English Sonnet for his rhyme-poor native tongue: three Sicilian quatrains followed by a heroic couplet (ababcdcdefefgg). The first stanza sets a situation or problem, and the second comments on it or resolves it.