By heteronormativity we mean …

By heteronormativity we mean the institutions, structures of understanding, and practical orientations that make heterosexuality seem not only coherent — that is, organized as a sexuality — but also privileged. It’s coherence is always provisional, and its privilege can take several (sometimes contradictory) forms: unmarked, as the basic idiom of the personal and the social; or marked as a natural ideal or moral accomplishment. It consists less of norms that could be summarized as a body of doctrine than of a sense of rightness […] Heteronormativity is thus a concept distinct from heterosexuality. One of the most conspicuous differences is that is has no parallel, unlike heterosexuality, which organizes homosexuality as its opposite. Because homosexuality can never have the invisible, tacit, society-founding rightness that heterosexuality has, it would not be possible to speak of “homonormativity” in the same sense.

Michael Warner, ‘Fear of a Queer Planet’, Social Text, no. 29 (1991): 3 – 17.