For the record:
The “1st” wave was the suffragettes. Not so much an ideology as a movement.
2nd-wave feminism happened around the seventies. Started off as a movement, but quickly became infiltrated by cultural Marxists. Would later be used to rationalize much of the third-wave feminist nonsense.
3rd-wave feminism started off with the riot girl scene — female punk rockers with little to no talent or concept of propriety. It would eventually make its way to the universities to merge with what second-wave feminism had become (Womyn’s Studies) and the growing push for diversity and multiculturalism.
4th-wave feminism is characterized by intersectionality. (Because multiculturalism wasn’t “diverse” enough.) This one originated squarely in the universities with the feminist appropriation of LGBT issues and the advent of modern “Gender Studies”.
(“Gender Studies” actually used to refer to the branch of Womyn’s Studies that dealt with male/female relations. Back when there were still only TWO genders.)