Doctrine of foreign equivalents

A rule applied in United States trademark law which deals not (as one might expect) with identical trade marks registered by the same proprietor for the same (or approximately the same) goods or services (which would be analogous to one meaning of the word "equivalent" in the patents field), but with the meaning of foreign words. Not to be confused with the doctrine of equivalents in patent law, which is another matter altogether.
The rule requires courts and the TTAB to translate foreign words to enable them to decide whether they are registrable, or whether they are confusingly similar to existing marks.
According to the Trademark Manual of Examining Procedure, the test for applying the doctrine is "whether, to those American buyers familiar with the foreign language, the word would denote its English equivalent", and in the case of marks that are descriptive or generic, whether it would have that connotation to the American buyer. It does not go to the status of the word in a foreign language: thus in Carcione v. The Greengrocer, Inc., 205 U.S.P.Q. (BNA) 1075 (E.D. Cal. 1979) it was irrelevant that the expression "greengrocer" has a generic meaning in the original version of the English language, raising the interesting question, where do American consumers buy fruit and veg?