A batalha terminou hoje.

Here, a means the. It is the feminine singular definite article in Portuguese.

So:

• a batalha = the battle

Be careful: a can also be a preposition in other contexts, but in this sentence it is just the article the.

Because batalha is a feminine noun in Portuguese, so it takes the feminine article a.

• a = feminine singular the
• o = masculine singular the

Grammatical gender in Portuguese does not always match natural gender. A battle is not female in any real-world sense; batalha is simply a grammatically feminine word.

Usually, nouns ending in -a are often feminine, and batalha follows that pattern.

So:

• a batalha
• uma batalha

But remember, this is only a tendency, not a perfect rule. Portuguese has exceptions. In this case, though, batalha is definitely feminine.

Terminou is the pretérito perfeito of terminar.

It means:

• ended
• sometimes, depending on context, has ended

In this sentence, A batalha terminou hoje, it refers to a completed event in the past: the battle ended today.

Because the sentence describes a completed action.

• termina = ends / is ending in present-time contexts
• terminava = was ending / used to end or an ongoing/habitual past situation
• terminou = ended; the action is finished

So terminou is the natural choice if the battle is already over.

The subject is a batalha.

So literally:

• A batalha = the battle
• terminou = ended
• hoje = today

Portuguese does not need a separate word like it here. The noun a batalha itself is the subject.

Because Portuguese often uses the noun itself as the subject, without adding a separate pronoun.

In English, you might later say:

• The battle ended today. It was long.

In Portuguese:

• A batalha terminou hoje. Ela foi longa.

But in the original sentence, ela is unnecessary because a batalha is already stated.

Putting hoje at the end is completely natural in Portuguese. It works like placing today at the end in English:

• The battle ended today.

Portuguese is flexible, so you could also say:

• Hoje a batalha terminou.
• A batalha hoje terminou.
  This is possible, but less neutral in many contexts.

The most neutral version here is A batalha terminou hoje.

Because hoje already works as a time adverb by itself.

So Portuguese says:

• hoje = today
• amanhã = tomorrow
• ontem = yesterday

You normally do not say:

• em hoje ✘

Just use hoje alone.

In Brazilian Portuguese, batalha is approximately:

• ba-TA-lya

The important part is lh, which sounds like the lli in million for many English speakers, though not exactly the same in every accent.

So:

• ba
• TA
• lha ≈ lya

The stress falls on ta: ba-TA-lha.

In Brazilian Portuguese, terminou is approximately:

• ter-mi-NOU

The stress is on the last syllable:

• ter-mi-NOU

That final ou sounds roughly like oh in many Brazilian accents, not like English ow.

Yes. In many contexts, the Portuguese pretérito perfeito can correspond to either:

• ended
• has ended

So A batalha terminou hoje could match English The battle ended today and, depending on context, sometimes The battle has ended today.

English and Portuguese do not divide these meanings in exactly the same way.

Yes. Acabou is also very common and natural.

• A batalha terminou hoje
• A batalha acabou hoje

Both can mean The battle ended today.

A small difference:

• terminou focuses a bit more on coming to an end
• acabou often feels a bit more like is over / finished

In many everyday contexts, they are interchangeable.

Normally, no, not in a neutral sentence like this.

Portuguese usually needs the article here:

• A batalha terminou hoje.

Without the article, Batalha terminou hoje, it sounds unnatural in standard usage unless Batalha is being used as a name or in a very unusual headline-style context.

It is neutral and standard. It works in both formal and informal contexts.

• It is not slang.
• It is not especially literary.
• It is a normal, correct sentence in everyday Portuguese.

So it is a good model sentence for learners.