ergo

Etymology

It is borrowed from Latin ergō (“therefore”),^{[2][3][4][5][6]} which in Latin was a preposition meaning "in consequence of" or "on account of" (with the genitive) and, used absolutely, a particle meaning "therefore"; it is recorded from the Twelve Tables on.^[5][7] De Vaan explains it as a contraction of the phrase Latin *ē rogō (“from the direction (of)”), with the middle vowel lost, and compares ergā (“towards, next to”) and corgō (“forwards”);^[7] Merriam-Webster Unabridged likewise derives it from this assumed phrase.^[6] The first part is ē (“out of”), a form of ex,^[3][8] and the second a noun from the root of regō (“to direct, guide”),^[3][9][8] from Proto-Indo-European *reg- (“to move in a straight line”).^[3][4] Barnhart allows either this or *ē regō,^[8] and Klein prefers the latter.^[9]

Earliest recorded meaning

Hence, therefore, originally a word of logic: about 1390, in the A text of Piers Plowman (Vernon manuscript).^[10] Barnhart dates the Piers Plowman use to before 1376,^[8] and the OED's first quotation, from the Chester Plays, is from about 1400 or earlier.^[2]

Semantic evolution

In English the word was at first a term of logic, marking the conclusion of a syllogism, like therefore.^[2][10][3] In the late 16th century it was also used as a noun, for the word itself and hence for a conclusion (1590 to 1867), and once for a logic-chopper (1597),^[2] and briefly as a verb, to use the word ergo (1589).^[2] Merriam-Webster Unabridged notes that it is now often used to stress that an inference is illogical,^[6] and it still has a noun sense, an inferred conclusion,^[6] which the Shorter Oxford calls long rare.^[11]

Timeline

• c. 1390 – therefore, hence, originally in logic.^[10] Barnhart dates it to before 1376,^[8] the OED to about 1400 or earlier.^[2]
• 1589 – verb, to use the word ergo (obsolete).^[2]
• 1590 – noun, the word ergo itself; a conclusion (until 1867).^[2][11]
• 1597 – noun, a logic-chopper (a single use).^[2]

Meanings

Adverb

1. Therefore; hence; used to introduce a logical conclusion: The shop was closed; ergo, there was no bread for breakfast.^[12][6][2]
2. Used ironically, to stress that an inference does not follow.^[6]

Noun

1. (rare) An inferred conclusion.^[6][11]

Related words

• regent
• right

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
8. ^ a b c d e Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
9. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
11. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
12. ^ Collins English Dictionary (2023), Glasgow: HarperCollins