Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
au pair, au pair girl (nn.)
are the names widely used in the United States for the young woman who agrees to accept room and board in exchange for doing housework and helping care for the children of the household. The term au pair means literally that she will be treated “as an equal” and so will live as a member of the family. This locution is also used as an adjective, as in au pair girl, and as an adverb, as in She’s working au pair this year. Typically au pairs want to live abroad for a time in order to master a new language and culture. Pronounce it o-PER. This foreign phrase has no exact English synonym, and not every American knows what it means.
