An example of dichotomy is grouping mammals by those that live on land and those that live in water.
- division into two parts, groups, or classes, esp. when these are sharply distinguished or opposed
- Astron. the appearance of the moon or of a planet when half of the surface facing the earth is illuminated
- Biol. a dividing or branching into two equal parts, esp. when repeated
Origin of dichotomyClassical Greek dichotomia: see dicho- and -tomy
- A division into two contrasting parts or categories: the dichotomy between rural and urban communities; regards the division between nature and nurture as a false dichotomy.
- Astronomy The phase of the moon, Mercury, or Venus when half of the disk is illuminated.
- Botany Branching characterized by successive forking into two approximately equal divisions.
Origin of dichotomyGreek dikhotomiā from dikhotomos divided in two dikho- dicho- temnein to cut ; see tem- in Indo-European roots.
- A separation or division into two; a distinction that results in such a division.
- Such a division involving apparently incompatible or opposite principles; a duality.
- (logic) The division of a class into two disjoint subclasses that are together comprehensive, as the division of man into white and not white.
- (biology, taxonomy) The division of a genus into two species; a division into two subordinate parts.
- (astronomy) A phase of the moon when it appears half lit and half dark, as at the quadratures.
- (biology) Successive division and subdivision; successive bifurcation, as of a stem of a plant or a vein of the body into two parts as it proceeds from its origin.
- (biology) A fork (bifurcation) in a stem or vein.
From Ancient Greek διχότομος (dikhotomos, “equally divided, cut in half”).