1.NounSynonym of apartment building: any building comprising apartments.
"Heritage House is a ten-story apartment house for seniors in the heart of downtown."
2.NounA house comparable in size to a single-family house but comprising several apartments; typically not more than two or three stories tall and containing a single-digit number of apartments (such as two to six).
"Armitage House is a stately old home on Main Street; it was built in the 1910s as the private home of a local factory owner, and years later it was converted into a trendy apartment house. [tour bus banter]"