Mater iam secura est, quia filius domi adest.

Because it agrees with mater (mother), which is a feminine noun.

In Latin, adjectives usually match the noun they describe in:

• gender
• number
• case

So:

• mater = feminine, singular, nominative
• secura = feminine, singular, nominative

If the subject were masculine, you would expect securus instead.

Est means is, from esse (to be).

So Mater iam secura est literally means:

• Mother now secure is

More natural English:

• Mother is now at ease
• Mother is now no longer worried

Latin often uses est just as English uses is with an adjective.

Literally, secura means free from care, carefree, untroubled, or not worried.

In this sentence, the most natural sense is:

• reassured
• at ease
• no longer anxious

So the idea is not that the mother is generally a relaxed person, but that she feels safe or relieved because of the next clause.

Iam usually means now, already, or by now, depending on context.

Here it suggests a change of state:

• Mother is now / by now at ease

This implies that earlier she may have been worried, but that has changed.

Quia means because.

It introduces the reason:

• quia filius domi adest = because her son is at home / is present at home

So the sentence has:

• main clause: Mater iam secura est
• reason clause: quia filius domi adest

Latin does not have articles like the or a/an.

So filius can mean:

• the son
• a son
• her son
• his son

The exact meaning comes from context.

In this sentence, because mater has already been mentioned, English naturally understands filius as her son.

Filius is nominative singular.

It is nominative because it is the subject of adest:

• filius adest = the son is present

So in the clause quia filius domi adest, the son is the one doing the action/state of being present.

Adest means is here, is present, or is at hand.

It comes from:

• ad- = to, near
• est = is

So adest is more specific than plain est. It does not just mean exists or is; it means someone is present or has arrived and is here.

In this sentence:

• filius domi adest = the son is present at home

This helps explain why the mother feels reassured.

Domi is a special form meaning at home.

It is a locative form, used with a small group of nouns, especially words for places like:

• domi = at home
• ruri = in the countryside
• Romae = at Rome

So:

• domi adest = is present at home

Latin can also say in domo in some contexts, but domi is the normal compact way to say at home.

Latin word order is more flexible than English because the endings show grammatical relationships.

The sentence is:

• Mater iam secura est, quia filius domi adest.

A very English-like order would still be almost the same:

• Mater est iam secura, quia filius adest domi.

But Latin often places words for emphasis or style rather than strict subject-verb-object order.

Here:

• Mater comes first, setting the topic
• iam highlights the change to now
• secura comes before est, giving emphasis to the mother’s state
• domi appears before adest, naturally linking at home with is present

So the order is natural Latin, not random.

Sometimes Latin does omit forms of esse (to be), especially in poetry or very compact writing.

But in a straightforward prose sentence like this, keeping est and adest is normal and clear.

So:

• Mater iam secura est is the ordinary full form
• filius domi adest is also the ordinary full form

Latin often does not need subject pronouns, because the verb ending already helps identify the subject.

But here the subjects are not pronouns anyway:

• mater = mother
• filius = son

So Latin simply names the people involved and does not need extra words like she or he.

If a pronoun were used, it would usually add emphasis rather than just basic information.

Partly, yes, but not only that.

Latin subjects often come early, but first position can also show topic or importance. Here, starting with Mater makes good sense because the sentence is mainly about the mother’s emotional state.

So first position tells the reader:

• As for the mother, she is now at ease...

Then the reason follows:

• ...because her son is at home.

They are:

• mater — from mater, matris = mother
• iam = now, already
• secura — from securus, secura, securum = free from care, safe, at ease
• est — from sum, esse = to be
• quia = because
• filius — from filius, filii = son
• domi — special locative of domus, domus = home, house
• adest — from adsum, adesse = to be present

A very literal translation would be:

• Mother now secure is, because son at-home is-present.

That is not good English, but it helps show the structure.

A natural English translation would be something like:

• Mother is now at ease, because her son is at home.
• The mother is now reassured, because her son is home.

Both capture the idea well.