garden apartment

Short definition from Wiktionary

Noun

1. 1
   A detached mother-in-law apartment or cottage on the same parcel as the main house.
2. 2
   One of a set of low-rise apartment buildings built among landscaped grounds and often arranged around courtyards that are open at one end.
3. 3
   An urban apartment in a multistory building located at or below ground level.