• WordNet 3.6
    • n tautology useless repetition "to say that something is `adequate enough' is a tautology"
    • n tautology (logic) a statement that is necessarily true "the statement `he is brave or he is not brave' is a tautology"
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Webster's Revised Unabridged Dictionary
    • n Tautology (Rhet) 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.
    • ***
Century Dictionary and Cyclopedia
    • n tautology Repetition of the same word, or use of several words conveying the same idea, in the same immediate context. See dilogy.
    • n tautology 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 tautology Synonyms Redundancy, etc. See pleonasm.
    • ***
Chambers's Twentieth Century Dictionary
    • n Tautology taw-tol′ō-ji needless repetition of the same thing in different words
    • ***


Webster's Revised Unabridged Dictionary
L. tautologia, Gr. : cf. F. tautologie,
Chambers's Twentieth Century Dictionary
Gr. tautologiatauto, the same, legein, to speak.


In literature:

That is not tautology.
"Northern Nut Growers Association Report of the Proceedings at the Eleventh Annual Meeting" by Various
And somebody says, 'Yes, that is tautology, that is saying the same thing twice over in different language.
"Expositions of Holy Scripture" by Alexander Maclaren
To say that, if it increases, his wages increase is to be simply tautologous.
"The English Utilitarians, Volume II (of 3)" by Leslie Stephen
Your observation is therefore tautological.
"Happy Days" by Alan Alexander Milne
The text is not a mere tautology or repetition.
"Commentary on Genesis, Vol. II" by Martin Luther
The catalogue should complement the arrangement on the shelves, and not be tautological.
"The Private Library" by Arthur L. Humphreys
Tautology was the blemish of written and vocal speech.
"A Romantic Young Lady" by Robert Grant
Is it less tautology to describe a thing over and over again with lines, than it is with words?
"Modern Painters Volume I (of V)" by John Ruskin
It is simply tautology.
"Anarchism and Socialism" by George Plechanoff
And, besides, only see how full it is of tautology.
"My Schools and Schoolmasters" by Hugh Miller

In poetry:

Deep with divine tautology,
The sunset's mighty mystery
Again has traced the scroll-like west
With hieroglyphs of burning gold:
Forever new, forever old,
Its miracle is manifest.
"Sunset And Storm" by Madison Julius Cawein

In news:

To suggest that New Yorkers also hate Red Sox fans is therefore a bit tautological.
I suppose I have to go beyond banal tautologies such as, 'He was the best player.

In science:

Necessary and sufficient, in case R is simple, is that (after factoring out Inf R), if H is a subgroup of R whose closure is a finite dimensional real vector space, then H ∩ R++ = {0}, but this is practically tautological.
Non-direct limit of simple dimension groups with finitely many pure traces
It is practically tautological that the the pure trace space can be identified with the path space of the reduced Bratteli diagram (obtained by collapsing all multiple edges to single edges), which is a Cantor set.
Non-direct limit of simple dimension groups with finitely many pure traces
Its defining property is that tr π(L) = W (L); this is almost a tautology and in this sense we only ‘repackaged’ the information of the loop functional.
Large N Gauge Theory -- Expansions and Transitions
If the sheaf of differentials Ω1 X/k of X over k is ample and generated by global sections, then the set of k-rational points of X is finite, where ampleness of Ω1 X/k means that the tautological line bund le on Pro j(Ld≥0 Symd (Ω1 X/k )) is ample.
Remarks on rational points of varieties whose cotangent bundles are generated by global sections
Let πF : P(F ) → X be the natural morphism and OF (1) the tautological line bundle on P(F ).
Remarks on rational points of varieties whose cotangent bundles are generated by global sections