"Wait", I may hear you ask. "Aren't lesbians, you know, women?"
Well... often yes. (Though there are some who are not women, and identify as other genders, such as non-binary, like me.) However, there are also specific gender identities that lesbians may use to describe their identities in more detail, using gender markers unique to lesbians, most notably butch and femme.
In Western popular culture, butch and femme are held in opposition to one another and are often paired in romantic or sexual couplings, seen as a sort of gay version of a heteronormative man-woman pairing. But there is so much more nuance to these personas than these assumptions of butch and femme gender identities.
Multiple authors, like Lucy Jones, Alison Eves, and Don Kulick consider butch and femme identities to be subversive critiques of the hegemonic position of heterosexuality, created in specific contexts. These identities are distinct forms of gender presentation, play, and even erotic role-play, used in the mirroring of desire, approaches to emotional connection, and other aspects of gender and sexuality. They are spectrums of feminine identity, using conscious choices of styles, gender performance, and stereotypes to build distinctly lesbian personas.
Butch identity is not necessarily the acceptance of 'masculine' ways of doing and being, but instead a rejection of the 'feminine' ways. There may be a focus on the feminine stereotypes of dress (skirts, long hair), behaviour (polite, nurturing), posture (sitting upright, taking up little room), and so on, and a distinct choice to not follow those stereotyped behaviours. Rather than being an inversion of feminine gender to masculine gender, butch is instead a projection of a specifically lesbian gender identity, distinct from both normative femininity and masculinity.
Femme identity, on the other hand, is a different projection of lesbianism as gender. Feminine stereotypes, especially regarding style and beauty, are leaned into and subverted. Presentations of femininity or hyper-femininity are used to comment and critique heteronormative standards by emphasizing certain aspects of visual appearance and behaviour, while embodying other non-normative feminine practises, namely attraction to, and relationships with, other feminine people.
Both butch and femme lesbian genders are used as, "specific patterns of sexual practice and desire, as well as being subversive re-appropriations of masculinity and femininity". However, since there are so many different ways of presenting butch, femme, or otherwise, there is a bit of an issue with homogenizing so many different identities into two very general categories. Historically, lesbian gender identities (as well as queer people in general) have been grouped together for cultural, political, and academic purposes, despite there being a huge variation in identity, presentation, and community practises. While these identities all subvert the mainstream gender and sexual structures of Western society, they all have a range of different practises, ideologies, and performances. Additionally, butch and femme are lesbian genders used by relatively few people, and lesbian as a label also does not include other cultural perspectives on gender and sexual identity. In academic studies on lesbian identity, many do not take other WLW or other gendered attraction into account (whether that be those who are not women, who experience multiple gendered attraction, or otherwise do not identify as lesbian), and also do not note the other categories which play into identity-building, such as racialisation, class, age, (dis-)ability, and so on. Keep these issues in mind when reading my posts, or others' works on lesbian gender identity.