tauto-, taut- +
2. The redundant repetition of a meaning in a sentence, using different words.
3. In rhetoric, a tautology is the use of redundant language in speech or writing, or, put simply, "saying the same thing twice".
4. In logic: a compound propositional form all of whose instances are true, as “A or not A”; a proposition or statement that, in itself, is logically true; as, "Today, that competing swimmer will win or will not win."
2. The relationship that exists between two structural isomers that are in chemical equilibrium and freely change from one form to the other.
2. A taxonomic designation; such as, Gorilla gorilla and Apus apus (common swift); in which the genus and species names are the same, commonly used in zoology but no longer in botany.
3. Words that are double strings: "The following words are tautonyms: beriberi, booboo, coco, mama, murmur, and papa."
Absolute tautonymy is the identical spelling of a generic or subgeneric name and the specific or subspecific name of one of its originally included nominal species or subspecies.
Linnaean tautonymy is the identical spelling of a new generic or subgeneric name established before 1931 and a pre-1758 name cited as a synonym of only one of the species or subspecies originally included in that genus.
Virtual tautonymy is the nearly identical spelling, or the same origin or meaning, of a generic or subgeneric name and the specific or subspecific name in a binomen or trinomen (not a term regulated by the International Code of Zoological Nomenclature).
2. The type of a genus whose species-group name is identical in spelling with the genus-group name.
Tautonymy is the possession by two or more distinct plants or animals of the same generic and specific names which are prohibited by the rules of scientific nomenclature; for example to refer to an animal as a "bison" and a plant identified as a "bison weed".The type of a genus whose species-group name is identical in spelling with the genus-group name.