From Longman Dictionary of Contemporary Englishpied-à-terrepied-à-terre /ˌpjeɪd æ ˈteə $ piˌed ɑː ˈter/ noun [singular] DHHa small apartment or house, often in the centre of a city or town, that is not your main home but which you own and stay in sometimes They kept a pied-à-terre in London for theatre evenings.
