Gay is now the most general informal term for "homosexual". It began to be used in this sense from around the 1920s. In the 19th century, "gay ladies" had meant prostitutes.
Its first use meaning "homosexual" in a film is thought to have been in Bringing up Baby in 1938.
In the 1970s "gay" was generally applied to both sexes, but it is now more commonly used to refer specifically to men, hence the more general phrase "gay and lesbian" came into use, subsequently overtaken by LGBT and its numerous variants (also known as the 'alphabet soup').
By some it is no longer thought correct to use "gay" as a noun, hence "He's gay" is preferred to "He's a gay", and "gay people" to "gays".
Sometimes, particularly among school children, "gay" is used as a generic term expressing disapproval, with no specific reference to homosexuality.
- 'The core belief of critical queer theorists is that homosexuality is not a part of human nature because there is no such thing as human nature; and that everything is socially constructed, even the body. Because heterosexuality is the overwhelming norm, and homosexuality the exception, and because society is nothing but a complex of oppression, homosexuals are defined by their rejection of heteronormativity' from The Queers Versus The Homosexuals: We are in a new era. And the erasure of gay men and lesbians is intensifying by Andrew Sullivan (Blog 2023)