An apartment usually found with its entrance on the side of someone's house, this phenomenon is most commonly found in Staten Island NY (on the south shore) The residents of side apartments usually consist of divorced mothers and dirtbags. Most drive an Infiniti which can usually be found parked illegally ( blocking someone's driveway) on the street. These people are overly tan and sometimes addicted to prescription pills.
Joe: Hey did you hear about mike?
vinny: no, what happened?
Joe: He paid 50G for a brand new Infiniti and 2 days later he was found OD on oxy.
Vinny: where?
Joe: his side apartment in great kills