before vowels thanat-, word-forming element meaning "death," from Greek thanatos "death," from PIE *dhwene- "to disappear, die," perhaps from a root meaning "dark, cloudy" (compare Sanskrit dhvantah "dark"). Hence Bryant's "Thanatopsis", with Greek opsis "a sight, view."
dark variety of Chinese tea, 1844, from Chinese wu-lung, literally "black dragon."
herbaceous plant much valued medicinally in Middle Ages, late 14c., from Old French verveine (13c.), from Latin verbena (see verbena).
Old English sweart "black, dark," of night, clouds, also figurative, "wicked, infamous," from Proto-Germanic *swarta- (source also of Old Frisian, Old Saxon, and Middle Dutch swart, Dutch zwart, Old Norse svartr, German schwarz, Gothic swarts "dark-colored, black"), from PIE root *swordo- "dirty, dark, black" (source of sordid). The true Germanic word, surviving in the Continental languages but displaced in English by black. Of skin color of persons from late 14c. Related: Swartest.
common spiny-finned freshwater fish, c. 1300, perche, from Old French perche, from Latin perca "perch," from Greek perkē "a perch," from perknos "spotted, having dark spots," from PIE root *perk- "speckled, spotted" (source also of Sanskrit prsnih "speckled, variegated;" Greek perkazein "to become dark"), typically in names of animals; compare Middle Irish erc, Welsh erch "spotted, dark red; salmon, trout," also "cow, lizard;" Old High German forhana, Old English forne "trout."
"partial darkness, state between light and darkness, twilight," 1620s, from an earlier adjective dusk, from Middle English dosc (c. 1200) "obscure, not bright; tending to darkness, shadowy," having more to do with color than light, which is of uncertain origin, not found in Old English. Middle English also had it as a verb, dusken "to become dark." The Middle English noun was dusknesse "darkness" (late 14c.).
Perhaps it is from a Northumbrian variant of Old English dox "dark-haired, dark from the absence of light," with transposition of -k- and -s-, (compare colloquial ax for ask). But OED notes that "few of our words in -sk are of OE origin." Old English dox is from PIE *dus-ko- "dark-colored" (source also of Swedish duska "be misty," Latin fuscus "dark," Sanskrit dhusarah "dust-colored;" also compare Old English dosan "chestnut-brown," Old Saxon dosan, Old High German tusin "pale yellow").
