This word is derived from the
proper adjective Lesbian = 'belonging to the island of
Lesbos' and has acquired its present day sense by association with the poet
Sappho. The word
lesbian was formerly applied to
homosexual women as a cover word or
euphemism, but it is now widely accepted as the term preferred by homosexual women themselves:
"All of us millions of lesbians and gay men were once American children." - Jean O'Leary and Bruce Voeller, New York Times
The original sense ('from Lesbos') has fallen out of use.