three, n. — Green’s Dictionary of Slang

three n.

1. (drugs) a $3 bag of heroin.

a.1955

‘Kitty Barrett’ in D. Wepman et al. Life (1976) 52: I reached in my slide and came out with two boss threes.

2. (UK gang, also 3) code used in posts or messages, usually preceding a name, to indicate respect for an imprisoned person.

2018-20

T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 3 code used in posts or messages, usually preceding a name, to indicate respect for an imprisoned person.

3. see finger n. (1b)

SE in slang uses

In derivatives

three-er (n.)

a three-year prison sentence.

1944

D. Runyon Runyon à la Carte 149: He is just after doing a three-er and it seems to leave some impression on him.

threesome (n.)

group sex involving three people of the same or mixed sexes.

1973		(con. 1930) E. Williams Emlyn 175: ‘Threesomes?’ ‘Good God, no.’.
1978		L. Kramer Faggots 178: We’ll find a big black stud and have a threesome.
1985		B. Humphries Traveller’s Tool 101: For the price of a couple of Baileys and Coke [...] they’d stack on a gleesome threesome.
1988		(ref. to 1960) in Walking After Midnight (1989) 88: [We] met some guy who was obviously cruising both of us [...] and we had a threesome.
1993		(con. 1950s) Kennedy & Davies Boots of Leather (2014) 199: These [lesbian] women threw parties in which they tried threesomes and daisy chains.
1999		Guardian 10 Sept. 16: The vases show us copulation in all its possible forms: vaginal, anal, fellatio [...] threesomes.
2003		www.thepantsman.com 🌐 It then got on to the topic of threesomes, and after some gentle persuasion [...] she told me how an ex-boyfriend and her had a threesome one night with one of her best female friends!

In phrases

three-a-dayer (n.)

(US drugs) one who smokes opium three times a day; thus multiples, i.e. four-a-dayer.

1937

‘Boxcar Bertha’ Sister of the Road (1975) 115: Anna and Jake smoked twice a day. There were in the group, however, ‘three-a-dayers,’ and ‘four-a-dayers.’.

three-six-nine (n.)

(US black) misbehavior, mischief, ‘funny businesss’ .

1936		Lil Johnson ‘New Shave ’Em Dry’ 🎵 I’m gonna tell you-all women and please understand / Don’t start no three-six-nine with my man / ‘Cause if you do you’ll surely get down [?] wrong / I got a forty-four that puts your waters on.
1938		H. Morand ‘Don’t Start No Stuff’ 🎵 I’ll treat you nice, I’ll treat you kind / But I don’t want no three-six-nine.

three, three, twenty-one (n.)

(N.Z. prison) a puniashment for possession of drugs, i.e. three ays in solitary confinement, three days’ Loss of Remission and 21 days off privileges.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 189/1: three, three, twenty-one (also 3 3 21) n. a punishment for the possession of drugs.

three times ten (n.)

(UK Und.) a thorty-day sentence.

1904

Salt Lake Herald (UT) 19 Oct. 5/1: Jimmy gets off with the beak handing him three times ten.