In domo bene vivitur, si omnes inter se consentiunt.

Because in can take either the ablative or the accusative, depending on the meaning.

• in + ablative = in / inside / at a place
• in + accusative = into / onto / toward a place

Here the sentence describes location, not motion: in the house / at home, so Latin uses the ablative: in domo.

It is. Domus is the dictionary form, meaning house, home.
In this sentence it appears in the ablative singular, which is domo.

So:

• domus = house/home
• domo = in the house / at home / from the house, depending on context

Here, with in, it means in the house.

Vivitur is an example of the impersonal passive.

Literally, vivitur means something like it is lived, but in natural English we usually translate it more smoothly as:

• people live
• one lives
• life is lived

So In domo bene vivitur means people live well in the house or life is good in the house.

Latin often uses this impersonal passive to make a general statement without naming a specific subject.

Because impersonal verbs in Latin are usually put in the third person singular, even when the idea is general.

So vivitur does not mean that only one person lives. It means something more general, like:

• one lives
• people live
• there is good living

This is a structure English does not use in the same way, so it can feel strange at first.

Bene is an adverb meaning well.

It modifies vivitur, so the idea is:

• one lives well
• people live well
• life goes well

In this sentence, bene suggests that life in the household is pleasant, successful, or harmonious.

Si means if and introduces a conditional clause.

So the sentence is divided like this:

• In domo bene vivitur = life goes well in the house
• si omnes inter se consentiunt = if everyone agrees with one another

The second part gives the condition under which the first part is true.

Omnes means all or everyone.

Here it is the subject of consentiunt, so it means all the people or everyone in the household.

It is nominative plural:

• masculine/feminine nominative plural: omnes

Since the sentence is general, Latin does not need to specify exactly who these people are.

Inter se means among themselves or with one another.

• inter = among, between
• se = themselves

Together, inter se expresses mutual relationship: the people are in agreement with each other, not just in general.

This is an extremely common Latin expression.

Because consentire already means to agree, to be in harmony, or to feel together. It does not need a direct object here.

So:

• omnes consentiunt = everyone agrees
• omnes inter se consentiunt = everyone agrees with one another

The phrase inter se adds the idea of mutual agreement more clearly.

Latin word order is more flexible than English word order because the endings show each word’s function.

So this sentence could be rearranged in several ways without changing the basic meaning, for example:

• Si omnes inter se consentiunt, in domo bene vivitur.
• Bene in domo vivitur, si omnes inter se consentiunt.

However, the original order is natural and effective:

• In domo sets the scene first
• bene vivitur gives the main idea
• si omnes inter se consentiunt gives the condition

So the order helps emphasis and flow, even though the grammar would still work in another arrangement.

Yes, depending on context, in domo can suggest not just the physical building but the household or home life.

So the sentence may mean more than merely inside the house physically. It can imply:

• in the home
• in the household
• family life goes well

That is often how a Latin speaker would understand it in a proverb-like sentence such as this one.

Consentiunt is:

• third person plural
• present tense
• active voice
• from consentio, consentire

So it means:

• they agree
• they are in agreement

Its subject is omnes, which is why the verb is plural.

Because the whole point of the impersonal passive is to avoid naming a subject. Latin is making a general statement:

• not this person lives well
• not they live well
• but life is lived well / people live well

This gives the sentence a broad, almost proverbial tone. It sounds like a general truth about household life.