Dichotomy
A dichotomy is a division into two non-overlapping or mutually exclusive, jointly exhaustive, parts. They are often contrasting and spoken of as "opposites". The term comes from dichotomos (divided): dich- ([in] two) temnein (to cut).
In biology, a dichotomy is a distribution of genera into two species. Such dichotomies are used as part of the process of classifying species, to build a taxonomic key. When classifying, a series of questions is asked which narrows down what is being examined, to indicate where it belongs in the hierarchy.
A well known dichotomy is the question "does it have a backbone?", used to divide species into vertebrates and invertebrates.
A false dichotomy is not jointly exhaustive or not mutually exclusive.
