‘Non-binary’ is an adjective that refers to people whose gender does not fit within the binary model of gender, as they are not, not completely or not always “men” or “women”. People often use the noun ‘enby’ – derived from the acronym NB – too.
‘Non-binary’ is an umbrella term that includes different gender identities. Some non-binary people have a gender “somewhere in-between woman and man”, some locate themselves completely outside this binary system and some experience their gender in a fluid way, i.e. changing over time.
As for all people, non-binary folks’ gender identity is independent from how their bodies look, what legal gender appears in their birth certificate and which names and pronouns they use. Many non-binary people describe themselves as trans. However, this does not apply to all enbies.