From traditional household etiquette:
老爷 (lǎoye) = master,
老太太 (lǎotàitai) = lady of the house,
少爷 (shàoye) = young master,
少奶奶 = young master's wife. The Zhang Ailing / Eileen Chang era of Republican-Shanghai fiction is where the term is most evocative. In modern jokes
阔太太 (kuòtàitai) and
阔少奶奶 mock the same archetype.