"amorous trifling; giddy behavior," 1718, noun of action from flirt (v.) as though Latin. The date, alas, gives the lie to Chesterfield's charming story of its coinage (in The World, Dec. 5, 1754) but not his refinement of the definition: "[F]lirtation is short of coquetry, and intimates only the first hints of approximation, which subsequent coquetry may reduce to those preliminary articles, that commonly end in a definitive treaty."

medieval Spanish county and later kingdom, from Vulgar Latin *castilla, from Latin castella, plural of castellum "castle, fort, citadel, stronghold" (see castle (n.)); so called in reference to the many fortified places there during the Moorish wars. The name in Spanish is said to date back to c.800. Related: Castilian. As a fine kind of soap, in English from 1610s.

"that is no longer practiced or used, out of date, gone out of use, of a discarded type," 1570s, from Latin obsoletus "grown old, worn-out," past participle of obsolescere "fall into disuse, be forgotten about, become tarnished," which probably is from ob "away" (see ob-) + an expanded form of solere "to be used to, be accustomed" (see insolent).

Middle English rein, from Old English regn "rain, descent of water in drops through the atmosphere," from Proto-Germanic *regna- (source also of Old Saxon regan, Old Frisian rein, Middle Dutch reghen, Dutch regen, German regen, Old Norse regn, Gothic rign "rain"), with no certain cognates outside Germanic, unless it is from a presumed PIE *reg- "moist, wet," which may be the source of Latin rigare "to wet, moisten" (see irrigate).

Rain dance "dance performed by a tribal group in hope of summoning rain" is from 1867; rain date in listings for outdoor events, giving an alternative date should rain interrupt them on the intended day, is from 1948. To know enough to come in out of the rain (usually with a negative) "take ordinary measures for one's protection" is from 1590s. Rain-shower is Old English renscur. Rain-gauge "instrument for collecting and measuring the amount of rainfall at a given place" is by 1769.

"to sleep lightly or fitfully; fall into a light sleep unintentionally," 1640s, probably from a Scandinavian source (compare Old Norse dusa "to doze," Danish døse "to make dull," Swedish dialectal dusa "to sleep") and related to Old English dysig "foolish" (see dizzy). Perhaps originally a dialect word in English and earlier than the attested date. Related: Dozed; dozing. As a noun, "a light sleep or slumber," from 1731. To doze off is by 1829.