'Bisexual' refers to people who are sexually attracted to people of either sex. Not everyone who experiences both kinds of relationship will necessarily identify themselves as bisexual. 

'Transgender' describes a range of different situations. 'Transsexual' people have the physical characteristics of one sex, but feel that they belong to the other. 'Transvestites' have no desire to change their sex but like to cross-dress. 'Transgender' people may identify themselves as either heterosexual or lesbian/gay.

Young people who are uncertain of their sexuality and still thinking about it are sometimes referred to as: 'questioning'.

'LGB' (lesbian, gay and bisexual) and 'LGBT' (lesbian, gay bisexual and transgender) are commonly-used abbreviations. 

'Self-realisation' is the process all lesbians and gays experience, as they come to understand that their sexuality is different from most. This may happen a long time (usually years) before a person starts to communicate with others about their sexuality.

'Coming out' is the term which describes the act of communicating with another person about one's sexuality.

'Heterosexism' refers to the way in which society is built on the assumption that everyone should be heterosexual.

'Heteronormative' refers to cultures where heterosexuality is encouraged and other identities are ignored or responded to negatively. A heteronormative society disregards the reality of sexual diversity. The educational and social needs of lesbians, gays and others, and the needs of their families, are ignored.

'Homophobia' describes the irrational fear that some people and institutions hold of lesbian and gay people and homosexuality in general.

'Queer' is a word which was once intended to be offensive, but it has been re-adopted by the gay community. 'Queer politics' emerged in the late 1980s and 1990s and is commonly used in academic fields. It was a reaction to separate groups and narrow identities, and might be regarded as a more inclusive title, being an umbrella term which covers lesbian, gay, bisexual and transgender individuals, as well as some heterosexual people.