Homosexuality (from Ancient Greek ὁμός, meaning "same", and Latin sexus, meaning "sex") is romantic attraction, sexual attraction or sexual behavior between members of the same sex or gender. As an orientation, homosexuality refers to "an enduring pattern of or disposition to experience sexual, affectionate, or romantic attractions" primarily or exclusively to people of the same sex. "It also refers to an individual's sense of personal and social identity based on those attractions, behaviors expressing them, and membership in a community of others who share them."
Gay is a term that primarily refers to a homosexual person or the trait of being homosexual. The term was originally used to refer to feelings of being "carefree", "happy", or "bright and showy". The term's use as a reference to homosexuality may date as early as the late 19th century, but its use gradually increased in the 20th century. In modern English, gay has come to be used as an adjective, and as a noun, referring to the people, especially to gay males, and the practices and cultures associated with homosexuality.
A lesbian is a female who expresses romantic or sexual attraction to other females, whether primarily or exclusively, or a female who self-identifies as lesbian. The term is also used as a noun, to refer to girls or women who are characterized by others as having the primary attribute of female homosexuality, or as an adjective, to describe characteristics of an object or activity related to female same-sex attraction.