Fortess. Extended Family. Political enity. Sub-set in the cult of Lolth. Administration. Military base.
A House is all these things.
Houses are based in Compounds.These may also be known as Houses to add to the confusion for any worthless outsider (who's opinion doesn't matter anyway.).
A compound usually consists of several stalactites connected by walls and fences. Within this perimeter there are ordinary buildings for housing troops, slaves supplies etc.
It is common for the nobility to excavate their homes in the stalactites themselves. Tunnels and suchlike are present as well of course.