c.1400, "a blow, stroke," perhaps originally imitative of the sound of patting. Meaning "light tap with hand" is from c.1804. Sense of "that which is formed by patting" (as in pat of butter) is 1754, probably from the verb. Pat on the back in the figurative sense attested by 1804.
"aptly, suitably, at the right time," 1570s, perhaps from pat (adj.) in sense of "that which hits the mark," a special use from pat (n.) in sense of "a hitting" of the mark. The modern adjective is 1630s, from the adverb.
1560s, "to hit, throw;" meaning "to tap or strike lightly" is from 1714; from pat (n.). Related: Patted; patting. The nursery rhyme phrase pat-a-cake is known from 1823. Alternative patty-cake (usually American English) is attested from 1794 (in "Mother Goose's Melody, or Sonnets for the Cradle," Worcester, Mass.).
late Old English shortened form of Old English ofdune "downwards," from dune "from the hill," dative of dun "hill" (see down (n.2)). A sense development peculiar to English.
Used as a preposition since c.1500. Sense of "depressed mentally" is attested from c.1600. Slang sense of "aware, wide awake" is attested from 1812. Computer crash sense is from 1965. As a preposition from late 14c.; as an adjective from 1560s. Down-and-out is from 1889, American English, from situation of a beaten prizefighter. Down home (adj.) is 1931, American English; down the hatch as a toast is from 1931; down to the wire is 1901, from horse-racing. Down time is from 1952. Down under "Australia and New Zealand" attested from 1886; Down East "Maine" is from 1825.
"soft feathers," late 14c., from Old Norse dunn, perhaps ultimately from PIE root *dheu- (1) "to fly about (like dust), to rise in a cloud."
Old English dun "down, moor; height, hill, mountain," from Proto-Germanic *dunaz- (cf. Middle Dutch dunen "sandy hill," Dutch duin, "probably a pre-insular loan-word from Celtic" [Cambridge Dictionary of English Place-Names], in other words, borrowed at a very early period, before the Anglo-Saxon migration.
The non-English Germanic words tend to mean "dune, sand bank" (cf. dune), while the Celtic cognates tend to mean "hill, citadel" (cf. Old Irish dun "hill, hill fort;" Welsh din "fortress, hill fort;" and second element in place names London, Verdun, etc.).
From PIE root *dheue- "to close, finish, come full circle." Meaning "elevated rolling grassland" is from c.1300. German Düne, French dune, Italian, Spanish duna are said to be loan-words from Dutch.
1560s, from down (adv.). Related: Downed; downing.
downer (1960s+ Narcotics)
[cool and teenager senses perhaps fr jazz musicians' terms like low down and down and dirty used to praise gutbucket and other jazz when especially well played]