Gay is most frequently used to describe a male homosexual although it is also sometimes used to describe female homosexuals.
Lesbians are female homosexuals.
Back in the 19th century a bill declaring homosexuality to be illegal was passed by the British parliament. Before becoming law it had to be signed off by Queen Victoria. She had no trouble sending all the males to places like Reading Gaol but she refused to sign off on the bill making Lesbians illegal. Why? Because her tiny mind couldn't conceive that any two women would do such a disgusting thing.
That's royalty for you. Too much inbreeding destroys the grey matter.