# Tautology

#### Pronunciation

*US***IPA:***/tɔˈtɒl.ə.dʒi/*

#### Origin

From *Late Latin* __tautologia__, from *Ancient Greek* __ταυτολογία__ from __ταὐτός__ (*tautós*, "the same") + __λόγος__ (*lógos*, "explanation")

## Full definition of tautology

#### Noun

#### tautology

(*countable and uncountable; plural*)

**tautologys**- (
*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". **1946**, Bertrand Russell,*History of Western Philosophy*:Pure mathematics consists of**tautologies**, analogous to ‘men are men’, but usually more complicated.- (
*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**.

#### Antonyms

- (
*linguistics: expression*) contradiction in terms - (
*in logic*) contradiction - (
*literary*) oxymoron

#### Coordinate terms

- (
*in logic*) contingency, contradiction