Since antiquity, there have been numerous terms for people who engaged in sexual or gendered behaviours considered “atypical”. In 17th-century Britain, for example, men who had sex with younger men were described as rakes, while in 1710 Molly was applied to effeminate men who participated in homosexual acts.

It was not, however, until the 19th century that the terms homosexual (1869) and heterosexual (1892) were coined, as part of a broader societal shift in viewing sexuality not as something you do (ie a behaviour) but as something you are (an identity).

Labels for these new sexual-identity categories emerged rapidly. Lesbian appeared in 1870 and by the turn of the 20th century was interchangeable with Sapphist and invert in the medical literature to describe homosexual women (with invert also referring to homosexual men).

The term gay did not acquire its current sense until the 1950s, though it took on a meaning of sexual freedom and licence 30 years before. In early 20th-century New York, some homosexual men adopted the word queer, originally meaning “deviant”, as their preferred self-reference term. Though it fell out of favour in subsequent decades as it became adopted as a term of abuse, queer was reclaimed as an umbrella term for the LGBT community in the 1980s by activist groups such as Queer Nation.

Bisexuality was coined at the same point in the late 19th century as heterosexuality was, though it was sometimes used to refer to sexual and romantic attraction (as it is today) and at other times to an individual’s biological characteristics (replacing terms such as hermaphrodite, or what we would today describe as intersex).

In 1965 psychiatrist John Oliven introduced the term transgender to replace the older transsexual. By the mid-1980s, transgender became the common label for people whose gender identity or gender expression does not match their sex assigned at birth. (In the 1990s the term cisgender was coined to denote those for whom it does.)

Over the past 20 years, there has been a growing movement against the perceived rigidity of these various sexual- and gender-identity categories. Inspired by the work of scholars like philosopher Judith Butler, individuals have begun labelling themselves in ways that seek to transcend binaries of sexuality (ie homo v hetero) and gender (woman v man).

The most common of these is queer, repurposed from its former meaning as an umbrella term for LGBT people to denote a refusal of traditional sexual-identity categories. Similarly, genderqueer (sometimes non-binary) is used as a label for individuals who reject conventional gender distinctions. Queer and genderqueer are labels for new ways of understanding and experiencing sexuality and gender. For this reason, they are labels we should respect — just as we respect the experiences they describe.

Erez Levon is reader in sociolinguistics at Queen Mary University of London