dichotomy

Etymology

It is borrowed from New Latin dichotomia (“division into two parts”), recorded in Latin from 1542,^[2][3][4] and directly borrowed from Ancient Greek διχοτομία (dikhotomía, “division into two parts”),^[2][5][6][7] which was used especially of the moon and in logic.^[2] The Greek noun comes from διχότομος (dikhótomos, “cut in two, divided equally”),^[2][8][7] formed from δίχα (díkha, “in two, apart”) and the stem of τέμνω (témnō, “to cut”).^[9][5][8] The first part is related to δίς (dís, “twice”), from Proto-Indo-European *dwo- (“two”),^[10][8] and the second comes from Proto-Indo-European *tem- (“to cut”), the root of tome and -tomy.^[10][7][5]

Earliest recorded meaning

Division into two sharply contrasting parts, especially in logic the division of a class into two mutually exclusive groups: 1588, in Abraham Fraunce's Lawiers Logike.^[2] The Shorter Oxford notes that the earliest records have the Latin form dichotomia.^[3] Barnhart and Merriam-Webster date the word to 1610,^[5][6] Etymonline to about 1600.^[10]

Semantic evolution

The word came into English as a term of logic for dividing a class or idea into two opposed parts.^[2][5] The Greek word was also an astronomer's term, and since 1661 English used it for the phase of the moon or a planet when exactly half its disc is lit.^[2] From 1707 botanists and zoologists used it for repeated forking into two branches.^[2][7] In the 20th century the logical sense was extended to a sharp or paradoxical contrast between two things, recorded from 1903;^[2][3] Mapping Metaphor places this use among the metaphors that describe contrast in terms of number, from the first half of the 20th century.^[11]

Timeline

• 1588 – division into two contrasting parts; in logic, division into two exclusive classes.^[2]
• 1661 – in astronomy, the half-lit phase of the moon or a planet.^[2]
• 1707 – in botany and zoology, forking into two branches.^[2]
• 1903 – a sharp or paradoxical contrast.^[2]

Meanings

Noun

1. A division into two contrasting or mutually exclusive parts or groups: the dichotomy between town and country.^[7][6][2]
2. A sharp contrast between two things or ideas that seem incompatible; a paradox.^[2][3]
3. (logic) The division of a class into two subclasses that exclude each other.^[2][6]
4. (astronomy) The phase of the moon, Mercury or Venus at which half of its disc is lit.^[7][2]
5. (botany) Branching by repeated forking into two roughly equal parts.^[7][2]

Word family

• dichotomically
• dichotomist
• subdichotomy
• dichotomize
• dichotomous

Related words

• dicho-
• -tomy
• tome
• anatomy
• atom

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
5. ^ a b c d e Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
6. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b c d e f g The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
8. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
10. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
11. ^ Mapping Metaphor with the Historical Thesaurus, University of Glasgow, mappingmetaphor.arts.gla.ac.uk