dichotomous

American  

[dih-kot-uh-muhs] / dɪˈkɒt ə məs /

adjective

1. divided or dividing into two parts.

2. of or relating to dichotomy.

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Other Word Forms

• dichotomously adverb
• dichotomousness noun
• nondichotomous adjective
• nondichotomously adverb
• undichotomous adjective
• undichotomously adverb

Etymology

Origin of dichotomous

1680–90; < Late Latin dichotomos < Greek dichótomos. See dicho-, -tome, -ous

Explanation

If something's dichotomous, it's divided into two distinct parts. It can describe a plant whose leaves pair off in opposing buds or anything — a government, a relationship — that has two divisions that are sharply opposed. The relationship between science and mysticism, or astrology and astronomy, for example, are two examples of a dichotomous relationship: each side has a completely irreconcilable set of basic principles. You might say the same about a father and son who support different baseball teams. Not surprisingly, the word dichotomous comes from the ancient Greek word dikhotomia, meaning "a cutting in half." So be warned and make sure your children grow up supporting the same team as you.

Example Sentences

Our recommendations support the use of probabilities instead of dichotomous “p-values” and the inclusion of findings from related studies to evaluate safety and effectiveness—an invaluable advancement for rare-disease research.

From The Wall Street Journal • Feb. 23, 2026

Mycologists use dichotomous keys to identify the species of mushroom based on its physical characteristics including the cap, stem, ring and gills.

From Los Angeles Times • Feb. 8, 2026

Stepping in for Mena, Dudamel, who assumes his Philharmonic post in 2026, led, in his only subscription concert appearances this season, a dichotomous program of dazzling crowd-pleasers and a thorny modernist work with utmost finesse.

From New York Times • Apr. 28, 2024

"Stress-boosted dichotomous thinking may thus well be a fundamental driver of belief rigidity," the authors wrote.

From Salon • Jul. 28, 2022

This colouring is more marked on the convex side, and it shows itself first in the cell on which the dichotomous branches are first produced, and which retains the darker tint longer than the other.

From Fungi: Their Nature and Uses by Cooke, M. C. (Mordecai Cubitt)