multiunit noun 2adjective 1forms 1 noun2 •A residential building containing multiple units or apartments."People see what's happening and they say 'Hey, this community is coming back.' So they come to the bank for a mortgage to buy one of the smaller multiunits, or a home. — 1988 •A unit consisting of multiple sub-units. adjective1 •Containing multiple units.These rooms are found in multiunit, multistory buildings that usually have commercial establishments at street level. — 1988 formsmultiunits