Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- n. Needless repetition of the same sense in different words; redundancy.
- n. An instance of such repetition.
- n. 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.
Century Dictionary and Cyclopedia
- n. Repetition of the same word, or use of several words conveying the same idea, in the same immediate context. See dilogy.
- n. The repetition of the same thing in different words; the useless repetition of the same idea or meaning: as, “they did it successively one after the other”; “both simultaneously made their appearance at one and the same time.” Tautology is repetition without addition of force or clearness, and is disguised by a change of wording; it differs from the repetition which is used for clearness, emphasis, or effect, and which may be either in the same or in different words.
- n. Synonyms Redundancy, etc. See pleonasm.
Wiktionary
- n. redundant use of words
- n. An expression that features tautology.
- n. A statement that is true for all values of its variables
GNU Webster's 1913
- n. A repetition of the same meaning in different words; needless repetition of an idea in different words or phrases; a representation of anything as the cause, condition, or consequence of itself, as in the following lines: -- . The dawn is overcast, the morning lowers, And heavily in clouds brings on the day. Addison.
WordNet 3.0
- n. (logic) a statement that is necessarily true
- n. useless repetition
Etymologies
- Late Latin tautologia, from Greek tautologiā, from tautologos, redundant : tauto-, tauto- + logos, saying; see -logy.
Examples
“This is the logical notion of tautology, which is very different from the way the term tautology is used in stylistics”
“Digital download? isnt that what they call a tautology?”
“It's only a tautology is you pretend life and niches don't have distinguishable properties and that a niche can't be populated.”
“And to say so is not to engage in tautology, which I think you were referring to, Andrew, when you made that remark about philosophy classes.”
“They argue that it is not a genuine claim about the real world but merely a truism, what philosophers call a tautology ” something true by the meaning of the words like ˜bachelors are unmarried.™”
“Cato - Its an absolute certainty that your close scrutiny revealed a tautology, which is an added bonus.”
“Homer Nods We erred yesterday in characterizing as a tautology the statement that if obese people outnumber the merely overweight, they must also outweigh them.”
“Will someone please explain to Egnor that a tautology is a kind of statement, not a kind of concept?”
“That is not a tautology, that is just being confused and contradictary”
“A tautology is a logical fact, one that is independent of any empirical observation.”
OK, Egnor, it's time to put up or shut up. - The Panda's Thumb
Lists
These user-created lists contain the word ‘tautology’.
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-ism's -logies
acosmism, absurdism, absolutism, ableism, aestheticism, alarmism, allotheism, anachronism, animalculism, analogism, animatism, animism and 464 more...
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Philosophy
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Greg's List
precarious, transient, evanescence, impermanence, fugacity, transitoriness, volatility, caducity, span, interregnum, effervescent, mine and 63 more...
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Literary critical terms
cathexis, catachresis, polyvocal, alterity, liminality, liminal, limn, erasure, metonymic, intertextual, intrapoetic, contradistinction and 66 more...
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fav1
ostensibly, fait accompli, edification, machination, vamp, abstruse, ebullient, tantamount, reductio, asymptotic, ad hominem, syllogism and 7 more...
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fancy essay words
hiatus, ontology, exegesis, hermeneutics, dialectics, demiurge, ascertain, contention, eschatological, synecdoche, centripetal, centrifugal and 86 more...
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tauto-
same
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Hapax Legomenon
For those special words that we only seem to use once in a lifetime..
hapax legomenon, schadenfreude, malapropism, ipso facto, carte blanche, tautology, pleonasm, reductio ad absurdum
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heaven16's list
Every cell in my body goes haywire when I hear people say, "It is what it is." And lately, everyone is saying it. Ugh!
Also, when you're going through tough times, and you need someone just t...

ruzuzu Ha! Apr 14, 2011
pterodactyl "Listen up! The first rule of Tautology Club is the first rule of Tautology Club!" Apr 14, 2011
wuwu4u 388 Sep 14, 2007
kafkaesque 'a tautology is a tautology' is a tautology Jan 19, 2007