tautology

tau·tol·o·gy

noun

The definition of a tautology is a statement that says the same thing twice in different ways, or a statement that has to be true by the way it is phrased.

The statement "the reason is because" is an example of a tautology because "the reason" and "because" are essentially the same thing said twice in different ways.
The statement "it is either right or it is left" is an example of a tautology because the statement by definition always has to be true.

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"tautology." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/tautology>.

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tautology. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/tautology

tautology

noun

pl. -·gies

1. needless repetition of an idea in different words; redundancy; pleonasm (Ex.: “necessary essentials”)
2. an instance of such repetition
Logic a proposition that is analytic (sense )

Origin of tautology

Late Latin tautologia from Gr: see tauto- and -logy

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MLA Style

"tautology." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/tautology>.

APA Style

tautology. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/tautology

tautology

noun

pl. tau·tol·o·gies

a. Needless repetition of the same sense in different words; redundancy.
b. An instance of such repetition.
Logic An empty or vacuous statement composed of simpler statements in a fashion that makes it logically true whether the simpler statements are factually true or false; for example, the statement Either it will rain tomorrow or it will not rain tomorrow.

Origin of tautology

Late Latin tautologia from Greek tautologiā from tautologos redundant tauto- tauto- logos saying ; see -logy .

Related Forms:

tau′to·log′i·cal tau′to·log′ic tau·tol′o·gous
adjective

tau′to·log′i·cal·ly tau·tol′o·gous·ly
adverb

THE AMERICAN HERITAGE® DICTIONARY OF THE ENGLISH LANGUAGE, FIFTH EDITION by the Editors of the American Heritage Dictionaries. Copyright © 2016, 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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Link to this page

Cite this page

MLA Style

"tautology." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/tautology>.

APA Style

tautology. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/tautology

Noun

(countable and uncountable, plural tautologies)

(uncountable) redundant use of words
It is tautology to say, "Forward Planning".
(countable) An expression that features tautology.
The expression "raze to the ground" is a tautology, since the word "raze" includes the notion "to the ground".
(countable, logic) A statement that is true for all values of its variables
Given a Boolean A, "A OR (NOT A)" is a tautology.
A logical statement which is neither a tautology nor a contradiction is a contingency.
A tautology can be verified by constructing a truth tree for its negation: if all of the leaf nodes of such truth tree end in X's, then the original (pre-negated) formula is a tautology.

Origin

From Late Latin tautologia, from Ancient Greek Ï„Î±Ï…Ï„Î¿Î»Î¿Î³Î¯Î± (tautologÃa) from Ï„Î±á½Ï„ÏŒÏ‚ (tautÃ³s, “the same") + Î»ÏŒÎ³Î¿Ï‚ (lÃ³gos, “explanation")

English Wiktionary. Available under CC-BY-SA license.