tom, n.⁴ — Green’s Dictionary of Slang

tom n.⁴

[the masculine name; euphemized by Ware as ‘one who does not care for the society of others than of her own sex’]

(UK society/US gay) a lesbian.

1909		J. Ware Passing Eng. of the Victorian Era 247/2: Tom (Street, 19 cent.). A masculine woman of the town. In higher ranks one who does not care for the society of others than those of her own sex.
1932		T. Croft Cloven Hoof 65: ‘Tom’ or ‘Rory’: a Lesbian woman.
1972		B. Rodgers Queens’ Vernacular 70: any gay woman [...] Tom (les sl).
1982		Maledicta VI:1+2 (Summer/Winter) 132: King (old term for diesel dyke, like tom).

old tom (n.)

1. (US) a lesbian.

1966		Trimble 5000 Adult Sex Words and Phrases 142: old tom (Sl.) 1. A Dyke, or other female Homosexual who gives that impression.
1972		R.A. Wilson Playboy’s Book of Forbidden Words.

2. (US) a prostitute catering to lesbians.

1966

Trimble 5000 Adult Sex Words and Phrases 142: old tom (Sl.) [...] 2. A Prostitute who caters to Lesbians, particularly Passive female clients.

3. (US gay) an old lesbian.

1972

B. Rodgers Queens’ Vernacular 71: the aging lesbian. [...] old tom.