There are two words used in the NT to refer to houses, oikos and oikia. We know from Xenophon that there was a Greek legal distinction between the physical building, oikia, and the heritable estate, oikos. This is general distinction is supported in NT usage, on the one hand, by the appearance of oikia in the NT passage most unambiguously about the physical building, Mt 7:24-27, the parable about the wise and foolish builders, and on the other hand by the uniform usage of oikos for lineage, i.e., one’s line of inheritance, Mt 10:6 ta probata ta apolwlota oikou Israhl, Lk 2:4 dia to einai auton ex oikou kai patrias Dauid. But the matter is not so simple. The two words are equally common in the NT and are often used in conpletely parallel syntactic and semantic environments: Lk 7:36 kai eiselqwn eis ton oikon tou farisaiou next to Mt 9:23 kai elqwn o Ihsous eis thn oikian tou arcontos. The question arises, if these two closely related forms mean different things, are the authors of the NT asserting something different in these otherwise similar passages or is it possible that the two words can be used interchangeably in some contexts? It will be argued in this paper that the latter is the case. Based on the cognitive process of metonymy different wordings can be used to refer to the same scenarios with no difference in meaning. We will discuss the fact that metonymy is based on the cognitive notion of a FRAME. Since frames are mental representations of encyclopedic knowledge, we will show from archeological evidence that the houses even in poor areas were more elaborate than a simple building, including both courtyard and storage areas. Hence the oikos, properly the whole complex, could stand for the oikia, properly the building, or vice versa. This result obtains in no small measure because one cannot have an oikos without having an oikia. We will look at implications of this for Biblical interpretation. For example, the NET very consistently translates oikos as home. We will discuss if that interpretation is warranted. References to the temple are consistently use oikos, eishlqen eis ton oikon tou qeou Mt 12:4, Mk 2:26, Lk 6:4 and mh toieite ton oikon tou patros mou oikon emporiou Jn 2:16. We will argue that this has its source in the regular LXX usage of oikos for tent: eiselqwn de Laban hreunhsen eis ton oikon Leias Gen. 31:33 (= Heb ’ohel), although there are clear cases in which oikos must mean household: sofai gunaikes wkodomhsan oikous, Prov. 14:1. We will conclude with a discussion tying in Howe’s recent work on metonymy and households.