late 14c., chekwede, applied to various plants eaten by chickens, from chick + weed (n.). In Old English such plants were cicene mete "chicken food."

"pertaining to the corpus luteum," 1906, from Latin luteus "yellow," from lutum, the name of a weed used in dying yellow, a word of unknown origin. Luteal phase is attested by 1932.

composite flowering plant of North America noted for the common allergic reaction to its pollen, 1790, from ragged + weed (n.); so called from shape of the leaves. The name had been applied to a different plant (ragwort) from 1650s.

c. 1600, figurative, "pointed, stinging," of writing, from Latin aculeatus "having a sting; thorny, prickly," also figurative, from aculeus "a sting, prickle," diminutive of acus "a needle" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). From 1660s in a literal sense, in zoology, "furnished with a sting;" by 1870 in botany.

early 15c., from weed + -y (2). In old slang, in reference to horses, "not of good blood or strength, scraggy, worthless for breeding or racing," from 1800; hence, of persons, "thin and weakly" (1852).

"tree of heaven," type of fast-growing weed-tree native to China, brought to Europe and America in 18c.; 1807, Modern Latin, from Amboyna Malay (Austronesian) ailanto, said to mean "tree of the gods." The spelling was altered by influence of Greek anthos "flower" (for which see anther).

"plant or plants growing in the sea," 1570s, from sea + weed (n.). Middle English had sechaf ("sea-chaff"), slauk, flet-wort  (Old English fleotwyrt: "float-wort"). Another Old English word for it was sæ war.

"notched on the edge like a saw," 1660s, from Latin serratus "sawlike, notched like a saw," from serra "a saw" (also a name of a type of serrated battle formation), a word of unknown origin. De Vaan suggests a connection to Latin sario 'to hoe, weed," and a PIE source in *sers- "cutting off." Related: Serrated; serrating.

"mad, crazy," 1844, American English, from Spanish loco (adj.) "insane," of uncertain origin, perhaps from Arabic lauqa, fem. of 'alwaq "fool, crazy person." Loco-weed was the name given to species of western U.S. plants that cause cattle and horse diseases that make them stagger and act strangely. But the adjective seems to be the older word.

globular fruit of a tree of Indonesia, 1580s, from Malay (Austronesian) durian, from duri "thorn, prickle." So called for its rind.

The durian is deemed by the Siamese the king of fruits. Its smell is offensive to European sense, and I have heard it compared to the stink of carrion and onions mingled. But the exquisite flavour of the fruit renders even its fragrance attractive to its habitués, and it is the only fruit which has ever a considerable money-value in the Siamese market. [Sir John Bowring, "The Kingdom and People of Siam," London, 1857]