Transgender describes a person whose gender identity differs from the sex recorded at birth. In UK and Irish legal practice it is primarily a descriptive term used in equality, employment, education, healthcare, prisons and family law, rather than a tightly defined legal category. In Great Britain, the Equality Act 2010 instead uses “gender reassignment” as a protected characteristic, which covers many (but not all) transgender people. In Northern Ireland, protection arises under sex discrimination, disability discrimination and human rights frameworks. In Ireland, the Gender Recognition Act 2015 and equality legislation protect transgender persons, including those with a gender recognition certificate. The term is relevant when advising on discrimination, harassment, victimisation, privacy, data protection, hate crime, access to services, single-sex and separate-sex spaces, and workplace policies. It is distinct from sexual orientation. Usage is broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland, but the precise statutory language and scope of protection differ by jurisdiction, so practitioners should cross‑check the applicable legislation and case law.