A person who is sexually attracted solely or primarily to others of the same sex.
Sexually and/or romantically attracted to members of the same sex, such as a man who is attracted to men or a woman who is attracted to women; gay. (Typically used in the sense of sole/exclusive attraction.)
Between two people of the same sex; gay.
A sexual orientation characterized by the potential for aesthetic attraction, romantic love and/or sexual desire for people regardless of their gender or sex.
Sexuality that encompasses all kinds of sexuality.