house: a dwelling, and by extension the people who live in it and the property it represents.
TranslatabilityPartialCertaintySettled
At its core this word names a house: the building people live in. From there the meaning reaches outward the same way the English word "house" does. The people who share the dwelling are the household, so "his whole house believed" means his family and everyone under his roof. The things a person owns can be called their "houses," so to "devour widows' houses" is to strip them of their property and estates.
These are not separate words that happen to sound alike. They are one picture seen from different angles: a place that holds a life together, the people it holds, and the means that sustain them. That is why a single sentence can move from the building to the family inside it without any awkwardness.
The New Testament also stretches the word once past anything physical. Paul calls the mortal body an earthly "house," a tent we live in now, set against a permanent dwelling from God. The familiar idea of a place that shelters us becomes a way to speak about the body itself.
Nuances
1athe house as a building: the dwelling people live in, enter, and gather in.
this word can still picture the physical building, which "household" cannotMat 7:24Act 12:12
Both
both can name the family and dependents living together under one roofMrk 3:25Php 4:22
Only household
"household" names only the people and their domestic life, dropping the building the word also carries
“home”
Comparison data is not available for this English gloss yet.
How oikia differs from similar Greek words
οἶκοςthe other common "house" word, leaning more toward the household, family line, and the temple as God's house, where this word leans more toward the physical dwelling.
Names the building itself as a structure that gets built, stands, or falls, so it can be founded on rock or on sand and be tested by the storm.Mat 7:24Mat 7:27Luk 6:48
Stands for the people who live together in it, the household as a single unit that can be split by feuding or greeted as a whole.Mat 12:25Mrk 3:25Mat 10:12
Names the indoor space you are welcomed into and hosted in, where guests recline at the table and a meal is served.Mat 26:6Mrk 14:3Luk 7:37
Counts as property that can be owned, given up, or stolen: houses left behind for the sake of Jesus, or swallowed up by men who prey on widows.Mat 19:29Mrk 10:30Mrk 12:40
Both
Both belong to one ordinary family dwelling, the roof above and the rooms below, so the same house can be named either way: in the warning about sudden flight, whoever is caught on the roof must not climb down to fetch anything from inside.Mat 24:17Mrk 13:15Luk 17:31
Names only the flat roof on top of a house, the open platform you climb up onto, never the building or the people under it.Act 10:9Luk 5:19
Because the roof is out in the open and in view of the whole neighborhood, it stands for making something public: what was whispered indoors is shouted from up here for everyone to hear.Mat 10:27Luk 12:3
It is a way in and out that bypasses the door: the friends of the paralyzed man went up onto it and lowered him through the tiles.Luk 5:19
Names a built structure, something put up on a foundation that can stand through a storm or collapse in one, and that a thief has to break into.Mat 7:24Mat 7:25Mat 7:27Mat 24:43
Is an enclosed indoor space that shelters people: a lamp lights everyone inside it, and a sick woman lies in bed there.Mat 5:15Mat 8:14
Stretches from the building to the people living in it, so it can be greeted, judged worthy of a visitor, or split by a quarrel that ruins it.Mat 10:12Mat 10:13Mat 12:25Mrk 3:25
Both
Both are property a person can own and sell for cash. Acts lists them side by side as the two kinds of holding the first believers turned into money: houses and pieces of land.Act 4:34Act 5:3Mrk 10:29
Both are commonly identified by whose they are, and both then serve to place a scene: Peter's house, or the estates belonging to the leading man of Malta who took Paul in.Mat 8:14Luk 7:6Act 28:7
Names open ground, a marked off parcel valued as land itself, with nothing said about anything standing on it: a plot bought with betrayal money, on which a body could fall in the open.Act 1:18Act 1:19Act 5:3Act 5:8
Can be an outdoor spot known by name that people walk out to and stay in, such as the olive ground where Jesus prayed or the piece of ground by Jacob's well.Mat 26:36Mrk 14:32Jhn 4:5
oikia in the other biblical languages
בַּיִתHebrew“house: home”the main Hebrew "house" word, covering the same range of building, household, family line, and estate.
Names a dynasty or lasting family line, descendants across generations, a sense this concrete Greek word does not carry.2Sa 7:112Sa 7:16
Is the standard word for the temple, the LORD's house, which this Greek word is rarely used for.1Ki 6:1Isa 2:3
Stretches to a small container or the plain inside of a thing.Exo 25:27Gen 6:14
What scholars say about oikia
Standard lexica treat οἰκία as essentially synonymous with οἶκος in the New Testament, both ranging over the dwelling, the household or family living in it, and by extension property. BDAG distinguishes the building, the household as a social and economic unit, and the figurative use for the body in 2 Corinthians 5:1. The two words overlap heavily; οἶκος carries the household and dynastic line and the temple more strongly, while οἰκία tends toward the physical house, though the distinction is not rigid.
Sources
BDAG, s.v. οἰκίαlexicon
LSJ, s.v. οἰκίαlexicon
O. Michel, "οἶκος, οἰκία," TDNT 5:119-159dictionary