dyke, n. — Green’s Dictionary of Slang

dyke n.

also dike

[ety. unknown; ? f. dyked down, dressed up; certainly some lesbians have always dressed as men. Another theory suggests the gradual corruption of SE hermaphrodite to morphodite to dike and dyke and thence, with the masc. generic bull, to bull-dyke n. and bull-dagger under bull n.¹; however, the first use of bull-dyke n. appears to predate dyke, which may thus be an abbr.]

a lesbian.

c.1930		(ref. to late 19C) N. Kimball Amer. Madam (1981) 19: I had a housekeeper – usually an old dyke.
1932		‘R. Scully’ Scarlet Pansy 192: They went back after Miss Fish, who would not miss anything for the world, especially as the famous Bulls and Dikes were to be there.
1938		H.M. Anderson Strip Tease 31: — There are a few dykes [in burlesque] [...] Lesbians’.
1942		Berrey & Van den Bark Amer. Thes. Sl. §405/ 3: Masculine woman, [...] dike, dyke.
1948		H. McCoy Kiss Tomorrow Goodbye in Four Novels (1983) 253: I never saw such a crowd of dikes and faggots.
1957		Kerouac letter 24 May in Charters II (1999) 36: Gertrude Stein (that dreary old dike).
1958		T. Capote Breakfast at Tiffany’s 25: Of course I like dykes themselves. They don’t scare me a bit. But stories about dykes bore the bejesus out of me.
1962		F. Norman Guntz 113: A fat dyke, who had the charm of a drunken Irish navvy.
1967		L. Bruce Essential Lenny Bruce 216: Now dike is vernacular for lesbian.
1977		A. Brooke Last Toke 138: The gays, the white dikes and faggots having chosen the rickety buildings [...] as the unofficial but internationally known capital of queerdom.
1980		E. Folb Runnin’ Down Some Lines 159: There are several vernacular expressions for a lesbian: bull, bulldike, bulldagger, dike.
1980		T. Lewis GBH 236: ‘Besides, it [i.e. a ‘blue’ film] was lesbian stuff. Which doesn’t mean to say I’m a dike’.
1989		R.G. Barratt ‘Poofs on Parade’ in What Do You Reckon (1997) [ebook] [D]idn’t the poofs and the dykes get the hump? They [...] threatened Fred and his faithful followers with all manner of dreadful things.
1989		Kirk & Madsen After The Ball 103: A lesbian is beaten in the face, knocked to the ground and kicked repeatedly while attackers scream ‘dyke’ and ‘bitch’.
1990		(con. 1930s–60s) H. Huncke Guilty of Everything (1998) 235: He got involved in a group of dykes and whores.
1991		J. Osborne Déjàvu Act I: A black feminist dike from Khartoum / Took a nancy-boy up to her room ...
1992		R.G. Barrett White Shoes 143: Here comes Mary. She’s a dyke. And her brother’s a fairy.
1993		Dr Dre ‘Fuck Wit Dre Day’ 🎵 But here’s a jimmy joke about your mama that you might not like / I heard she was the ’Frisco dyke.
2000		J. Hawes Dead Long Enough 134: I can’t do this any more, everyone’ll think I’m a dyke.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] That miserable fuckin dyke.
2010		(con. 1973) C. Stella Johnny Porno 188: Big black bubble-butted bitch-dykes like skinny white girls inside the joint.
2012		(con. 1980s) I. Welsh Skagboys 37: Ah’m back under the harsh strip lights ay the workshop, sweatin like a blind dyke in a fishmonger’s.
2016		Young M.A. ‘Eat’ 🎵 Damn, I'm must really put fear in these niggas / Because they call me a dyke, a faggot, a gay bitch.
2019		P. Baker Fabulosa 292/1: dyke, dike a lesbian.
2020		D. Winslow ‘Crime 101’ in Broken 95: ‘[T]hose dykes in the joint [...] they’ll make a meal of a guera [i.e. a blonde/a white girl] like you’.