jam session, n. — Green’s Dictionary of Slang

jam session n.

[jazz use jam session, an impromptu concert. The first session, according to Mezzrow & Wolfe (1946), took place in late 1927 at 22 North State Street, Chicago, in the cellar of the Three Deuces speak-easy. Among those involved were Bix Beiderbecke, Bing Crosby and Mezzrow himself. ‘I think the term “jam session” originated right in that cellar. Long before that, of course, the colored boys used to get together and play for kicks, but those were mostly private sessions, strictly for professional musicians, and the idea was usually to try and cut each other, each one trying to outdo the others and prove himself best. Those impromptu concerts of theirs were generally known as “cuttin’ contests.” Our idea [...] was to play together, to make our improvisation really collective [...] to see could we fit together and arrive at a climax all at once. Down in that basement concert hall, somebody was always yelling over to me, “Hey Jelly, what you gonna do?” [...] and almost every time I’d cap them with, “Jelly’s gonna jam some now,” just as a kind of play on words. We always used the word “session” a lot, and I think the expression “jam session” grew up out of this playful yelling back and forth.’]

1. (orig. US) an informal gathering, a get-together, esp. of musicians, a group discussion.

1937		R.B. Nye ‘A Musician’s Word List’ in AS XII:1 47: Used only in reference to groups, who gather for jam sessions, in which each musician in turn improvises on a given melody which the others accompany.
1938		C. Beaton Cecil Beaton’s N.Y. 194: I have never been [...] to a ‘jam session,’ or to the Yankee stadium, where the swing sessions, starting at eleven in the morning, reduce, by tea-time, the audience to a jelly.
1946		Mezzrow & Wolfe Really the Blues 50: What a jam session we put on that night. Murph dragged out his trumpet, Rapp put his clarinet together, Frank Snyder set up his drums, I worked up enough guts to sit down at the piano.
1952		Kerouac letter 8 Feb. in Charters I (1995) 338: I [...] cut around the corner to little Harlem scene of the great jam sessions of 48 and 49.
1965		C. Brown Manchild in the Promised Land (1969) 293: They’d be coming up all times of the night, getting high smoking pot and having jam sessions.
1976		M. Braly False Starts 270: The three of us worked it together, split fifty dollars, and went over to North Beach to find a jam session.
1984		C. White Life and Times of Little Richard 165: He suggested a jam session on stage.
1993		R. Firestone Swing, Swing, Swing 44: [T]he Three Deuces, a hole-in-the-wall speakeasy at 222 North State Street, where they held nightly jam sessions.
2013		Antigua Obs. 24 May 🌐 We can actually really have it like a jam session.
2016		Jamaica Gleaner 19 Apr. 🌐 There was a stage, some equipment and the open invitation [...] to interested musicians to come and hold weekly jam sessions.
2023		(con. 1962) J. Ellroy Enchanters 284: Doc Shelley was a scenester [...] hung out at party pads, jam-session pads, fuck pads, and upscale call pads.

2. (W.I./UK black) any occasion which is accompanied by a large, boisterous audience.

1938		Pittsburgh Courier (PA) 27 Aug. 11/1: The Paramount Theatre [had] the best Jam-Session it has ever had.
1953		W. Hopson ‘The Ice Man Came’ in Thrilling Detective Winter 🌐 Bo-Bo slept through it all. He was the only one that did. Brrrother, what a jam session!
1990		(con. 1930s–60s) H. Huncke Guilty of Everything (1998) 287: It got so that we were having amphetamine jam sessions up there at all hours of the night.

3. sexual foreplay or intercourse.

1972		R.A. Wilson Playboy’s Book of Forbidden Words 149: Jam Session. A bout of sexual intercourse.
1985		O. Hawkins Chili 68: After a ten minute jam session, she whispered in my left ear, ‘Go ’head, baby . . . do what you want to do to me.’.