Binomial

noun
  1. A mathematical expression consisting of two terms connected by a plus or minus sign. noun
    The expression (x + y) is a simple binomial.
    In algebra, a binomial can be expanded using the binomial theorem.
  2. In biology, a two-part name used to denote a species, consisting of the genus name and the species identifier. noun
    The binomial for humans is Homo sapiens.
    Carl Linnaeus developed the system of binomial nomenclature.