IPA: /ˌhɛt.ə.roʊˈsɛk.ʃu.əl/
KK: /hɛtəroʊˈsɛkʃuəl/
Relating to or attracted to people of the opposite sex.
He identifies as heterosexual and is attracted to women.
A person who is attracted to people of the opposite sex.
She identifies as a heterosexual and is attracted to men.
Heterosexual → It is formed from "hetero-" (from Greek "heteros", meaning different) and "sexual" (from Latin "sexualis", meaning of or pertaining to sex). The word describes a sexual orientation characterized by attraction to individuals of the opposite sex.
Think of 'different' ('hetero-') when remembering that 'heterosexual' refers to attraction between opposite sexes.