O estádio está cheio hoje.

In normal Portuguese, singular countable nouns usually need an article when you are talking about a specific thing.

So o estádio = the stadium.

Just estádio by itself would usually sound incomplete in a full sentence like this, unless it appeared in a special context such as:

• headlines
• labels
• dictionary entries
• very telegraphic speech

So for standard everyday Portuguese, O estádio está cheio hoje is the natural form.

Portuguese has two main verbs for to be: ser and estar.

Here it uses estar because cheio describes a condition or state of the stadium at this moment, not a permanent characteristic.

• O estádio está cheio hoje = the stadium is full today
• O estádio é grande = the stadium is big

A good beginner rule is:

• ser = identity, characteristic, classification
• estar = current state, condition, location

Since the stadium is not permanently full, está is the right choice.

Está is the third-person singular present form of estar.

Full present tense of estar:

• eu estou
• você / ele / ela está
• nós estamos
• vocês / eles / elas estão

Since o estádio is singular, the verb must also be singular: está.

Because adjectives in Portuguese usually agree in gender and number with the noun they describe.

Estádio is:

• masculine
• singular

So the adjective must also be masculine singular:

• cheio

Examples:

• o estádio cheio
• a praça cheia
• os estádios cheios
• as praças cheias

This kind of adjective agreement is very important in Portuguese.

It can suggest either one depending on context.

In O estádio está cheio hoje, cheio most naturally means:

• full
• packed
• crowded

When talking about places, Portuguese often uses cheio the way English uses both full and crowded.

So in real usage, it can imply there are a lot of people there.

Yes. Lotado is very common in Brazilian Portuguese and often sounds even more natural when talking about a place packed with people.

Compare:

• O estádio está cheio hoje = The stadium is full/crowded today
• O estádio está lotado hoje = The stadium is packed today

Lotado can sound a bit stronger than cheio, though in many everyday situations they overlap.

Hoje is an adverb of time, and Portuguese is fairly flexible about where adverbs go.

All of these are possible:

• O estádio está cheio hoje.
• Hoje o estádio está cheio.
• O estádio hoje está cheio.

The version with hoje at the end sounds very natural and neutral.

Placing hoje first can give it a little more emphasis, like Today, the stadium is full.

No. Hoje by itself already means today, so no preposition is needed here.

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

You can sometimes use prepositions with time expressions in other contexts, but for a basic sentence like this, hoje stands alone.

In Brazilian Portuguese, estádio is pronounced approximately like:

es-TA-djoo

A few helpful points:

• The stress falls on tá because of the written accent: estádio
• The di before another vowel often sounds like j in many Brazilian accents
• So dio often sounds something like joo

A rough English-friendly approximation is:

es-TA-joo

Not exact, but close enough to help.

Cheio is roughly pronounced:

SHAY-oo

Helpful breakdown:

• ch in Brazilian Portuguese usually sounds like sh
• ei often sounds like ay
• final o is often pronounced like oo in unstressed position in Brazilian Portuguese

So cheio is approximately SHAY-oo.

Yes, absolutely. That is a very natural sentence.

Compare:

• O estádio está cheio hoje.
• Hoje, o estádio está cheio.

They mean the same thing. The difference is mostly emphasis and rhythm.

• Ending with hoje is very neutral
• Starting with Hoje highlights the time more

Both are correct in Brazilian Portuguese.

Yes. The subject is o estádio.

Sentence structure:

• O estádio = subject
• está = verb
• cheio = adjective / subject complement
• hoje = adverb of time

So the sentence follows a very common pattern in Portuguese:

subject + verb + adjective + time expression

In normal speech, that sounds incomplete or unnatural.

Standard Portuguese wants:

• O estádio está cheio hoje

You might see the article dropped in very special cases, such as:

• headlines
• notes
• sports commentary shorthand

But for regular conversation or writing, keep o.

The accent mark in estádio shows where the stress goes: es-TÁ-dio.

Without getting too technical, the accent helps you know that the strong syllable is tá, not another part of the word.

For learners, the most practical takeaway is:

• estádio → stress the tá

Accent marks in Portuguese are very important because they often affect pronunciation directly.