Back Translation (Mark Twain)

A "back-translation" is a translation of a translated text back into the language of the original text, made without reference to the original text.

In the context of machine translation, a back-translation is also called a "round-trip translation."

Mark Twain, back-translator

When translations are produced of material used in medical clinical trials, such as informed-consent forms, a back-translation is often required by the ethics committee or institutional review board.

Similarly, when historians suspect that a document is actually a translation from another language, back-translation into that hypothetical original language can provide supporting evidence by showing that such characteristics as idioms, puns, peculiar grammatical structures, etc., are in fact derived from the original language.