"ovate, pale yellow citrus fruit," c. 1400, lymon, from Old French limon "citrus fruit" (12c.), which comes via Provençal or Italian from Arabic laimun, Persian limun. Apparently brought from India to the Levant by the Arabs 9c. or 10c.; the word is perhaps ultimately from an Austronesian word of the Malay archipelago, such as Balinese limo "lemon," Malay limaw "citrus fruit, lime" (compare lime (n.2)).
Meaning "person with a tart disposition" is from 1863. For the sense "worthless thing," see lemon (n.2). Slang meaning "a Quaalude" is 1960s, from Lemmon, name of a pharmaceutical company that once manufactured the drug. The surname is from Middle English leman "sweetheart, lover." Lemon-juice is attested from 1610s; the candy lemon-drop from 1807. The East Indian lemon-grass (1837) is so called for its smell.
"large, thick-rinded, lemon-like citrus fruit," late 14c., also citrine (early 15c.), from Old French citron "citron, lemon" (14c.), possibly from Old Provençal citron, from Latin citrus "citron-tree," and influenced by lemon; or else from augmentative of Latin citreum (mālum) "citron (apple);" see citrus.
Apparently the citron was the only citrus fruit known to the Greeks and Romans; the word was used in English to also mean "lemon" or "lime" until the sense became restricted 17c.
1858 in reference to a type of fragrant grass, and especially to the oil it yields, from French citronelle "lemon liquor," from citron (see citrus). Originally an Asiatic grass used in perfumes and soaps, later applied to a substance found in lemon oil, etc. Related: Citronellic.
"lemon-colored, yellow or greenish-yellow," late 14c., from French citrin, from Latin citrus (see citrus). From 1879 as a color name.
"to make lame," c. 1300, from Proto-Germanic *lamejanan (source also of Old Saxon lemon, Old Frisian lema, Dutch verlammen, German lähmen, Old Norse lemja "thrash, flog, beat; to lame, disable"), from the root of lame (adj.). Related: Lamed; laming.