tautós

Tautós, or taútos, is a Greek root meaning "the same" or "identical." In modern scientific and scholarly terminology, tauto- is used as a productive combining form to indicate sameness or reversible interchange between states. The term enters English and other languages through Latin and Greek medical, scientific, and philosophical vocabulary.

In logic and linguistics, tautology refers to a statement or formula that is true by virtue of its form, often producing redundancy rather than new information. In biology and taxonomy, a tautonym (tautonymy) is a scientific name in which the genus and species are identical, such as Gorilla gorilla, reflecting the “same name” idea.

In chemistry, tautomerism describes the rapid interconversion between two isomeric forms of a compound that differ by the position of a proton and a double bond, commonly exemplified by keto–enol tautomers. A molecule that participates in this exchange is called a tautomer.

More broadly, tauto- appears in various scientific terms to denote sameness, identity, or interchangeable forms. The prefix derives from Greek and has been integrated into Latin and English technical vocabulary across disciplines.

See also: tautology, tautonym, tautomer.