Fiul este acasă.

Fiu means son in an indefinite sense, while fiul means the son.

Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

So:

• fiu = a son / son
• fiul = the son

In this sentence, fiul is definite, so it means the son.

The base noun is fiu. To make it definite, Romanian adds the definite article -l.

So:

• fiu → fiul

This is a normal Romanian pattern: the article is attached to the noun, not written as a separate word.

Fiul is pronounced roughly like FEE-ool, but smoothly, not as two strongly separated words.

A helpful approximation for English speakers is:

• fiu ≈ fee-oo
• fiul ≈ fee-ool

The f is like English f, and the iu combination may feel unfamiliar at first. Try saying it lightly and smoothly rather than over-pronouncing each vowel.

Este means is.

So:

• Fiul = the son
• este = is
• acasă = at home / home

In standard Romanian, you normally keep este in this kind of sentence.

However, in everyday speech, people very often shorten este to e:

• Fiul este acasă. = more formal or careful
• Fiul e acasă. = very common in speech

Both are correct.

Acasă means at home or simply home.

It is an adverb, not a noun here. That is why Romanian does not say something word-for-word like at the house in this sentence.

So:

• este acasă = is at home / is home

This is the normal Romanian way to express being at home.

Because Romanian usually uses a postposed definite article, meaning the article comes after the noun as an ending.

Compare:

• English: the son
• Romanian: fiul

This is one of the big structural differences between English and Romanian. English learners of Romanian often notice it immediately.

This is the most neutral and natural word order:

• Fiul = subject
• este = verb
• acasă = adverb of place

So Fiul este acasă is the basic way to say it.

Romanian word order can be more flexible than English, but changing the order often changes the emphasis. For example, putting acasă earlier can sound more marked or contrastive. For a learner, Fiul este acasă is the safest default pattern.

Yes. That is normal.

In English, we say at home, with a preposition. In Romanian, acasă already carries that idea, so no extra preposition is needed here.

So:

• English: is at home
• Romanian: este acasă

This is just how Romanian expresses the idea idiomatically.

By itself, fiul literally means the son.

Depending on context, it can sometimes be understood as the son or someone’s son, and in real life the context may make it clear whose son is being talked about. But grammatically, the sentence itself says the son is at home, not specifically my son is at home.

If you want to say my son is at home, Romanian would normally say:

• Fiul meu este acasă.

Yes, a big one.

• acasă = at home / home
• la casă usually means something like at the house, and in some contexts it can also mean at the checkout/cash register

So if you want to say someone is home, acasă is the correct word.

That makes Fiul este acasă the natural sentence for The son is at home.