"They're not like us, at all. They're toms."
Sappho and female friends depicted on a vase (c.440-430BC)
Creative Commons Attribution Share AlikeSappho and female friends depicted on a vase (c.440-430BC) - Credit: Marsyas, Wikimedia Commons

Toms (sometimes Tommies) was Victorian slang for lesbians, particularly boyish ones.

Other more orthodox 19th Century terms for lesbians were Sapphists (derived from the Ancient Greek poet Sappho) and tribades.

A Dictionary of Victorian sexual slang

Dictionary of the Vulgar Tongue (1811)