in-law apartment
noun /ˈɪn lɔː əpɑːtmənt/
/ˈɪn lɔː əpɑːrtmənt/
(also mother-in-law apartment, in-law suite
(all North American English) /ˈɪn lɔː swiːt/
/ˈɪn lɔː swiːt/
)(British English granny flat)
(informal)- a set of rooms for an old person, especially in a relative’s house