cloud nine, n. — Green’s Dictionary of Slang

cloud nine n.

[according to Brewer, Dict. of Phrase and Fable (15th edn, 1995), the term stems from the classification of clouds by the US Weather Bureau. There are nine divisions, and number nine is cumulonimbus, a cumulus cloud of great vertical extent, topped with shapes that resemble mountains or towers; cloud seven/eight/ten are presumably more/less blissful by degrees, but note seven is trad. a ‘lucky’ number]

1. (also cloud seven, cloud eight, cloud ten, nine) a state of bliss, sometimes drug-induced; also attrib.

1935		A.J. Pollock Und. Speaks 22/2: Cloud eight, befuddled on account of drinking too much liquor.
1956		O. Duke Sideman 120: Oh, she’s off on Cloud Seven — doesn’t even know we exist.
1959		I. Taylor ‘Kookie, Kookie, Lend Me Your Comb’ 🎵 Don’t cut out of here till we get on Cloud 9.
1963		M. Braly Shake Him Till He Rattles (1964) 121: I’ve got to try some of that stuff one of these days, see if I can ease up on that cloud-nine kick.
1963		G. Lambert Inside Daisy Clover (1966) 208: I can’t pretend I’m on cloud seven either.
1972		(con. 1960s) D. Goines Whoreson 228: Take that money, baby, and buy yourself a trip to cloud nine.
1983		R. Price Breaks 358: When Tony was feeling good I was on Cloud Nine.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 227: Claude was up on cloud ten.
1994		P. Baker Blood Posse 71: I can feel this Colombian red taking me to cloud nine.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 164: His brother tied off. His brother geezed. His brother untied on 9.
2011		‘Jack Tunney’ Split Decision [ebook] You ought to be on cloud nine, all the dough you’re into.
2012		R. Milward Kimberly’s Capital Punishment (2023) 57: Heaven [...] the heady delights of Cloud 9.
2021		J. Ellroy Widespread Panic 124: They fed a spike. They tied off tourniquets. They geezed [...] They hit Cloud 9.

2. (drugs) crack cocaine.

2001

ONDCP Street Terms 6: Cloud nine — Crack Cocaine.