binomial

Etymology

Formed from Late Latin binōmium + -al. The derivation of binōmium is unclear. It was used by Gerard of Cremona in the 12th century. Suggested sources are the Latin nōmen (“name”), the Ancient Greek νομός (nomós, “distribution, pasture”), or the Old French nom (“name”). Compare binomy and binominal, as well as the French binôme.

adj

1. Consisting of two terms, or parts.
   Finally, instead of returning to Chile’s traditional proportional representation system, the law adopted the “binomial” system, which gave strong incentives to the parties to form broad coalitions. 1992, Rhoda Rabkin, “The Aylwin Government and ‘Tutelary’ Democracy: A Concept in Search of a Case?”, in Journal of Interamerican Studies and World Affairs, volume 34, number 4, →JSTOR, page 139
2. (statistics) Of or relating to the binomial distribution.
   Assuming a normal approximation to binomial probabilities the proportion of total complications reported for 1979–85 in the age class 0–14 years was significantly higher than the proportion in the same age class for the period 1962–69 (p < 0·0001) 1991-11-23, D. J. Nokes, R. M. Anderson, “Vaccine safety versus vaccine efficacy in mass immunisation programmes”, in The Lancet, volume 338, number 8778, →DOI, page 1309

noun

1. (algebra) A polynomial with two terms.
2. (algebra) A quantity expressed as the sum or difference of two terms.
3. (taxonomy) A scientific name at the rank of species, with two terms: a generic name and a specific name.
   Common name followed by Latin binomial in parentheses. 1991, Daniel W. Gade, “Weeds in Vermont as Tokens of Socioeconomic Change”, in Geographical Review, volume 81, number 2, →JSTOR, page 169