O gato está miando.

O is the masculine singular definite article, equivalent to the in English.

So:

• o gato = the cat

In Portuguese, articles are used more often than in English. With animals, people, and everyday nouns, using the article is very natural when you mean a specific one or when the context makes it clear.

Because gato is the masculine form and gata is the feminine form.

• o gato = the male cat / the cat
• a gata = the female cat

Sometimes masculine can also be used in a general sense when the sex is unknown or not important. If you know the cat is female, you would usually say A gata está miando.

It is the structure estar + gerund, which is used to talk about an action happening right now or in progress.

Here:

• está = is
• miando = meowing

So está miando works like is meowing in English.

This is very common in Brazilian Portuguese:

• Estou estudando = I am studying
• Ela está falando = She is speaking
• O gato está miando = The cat is meowing

You can say O gato mia, but the meaning is a little different.

• O gato está miando = the cat is meowing right now
• O gato mia = the cat meows / the cat meows habitually / the cat is meowing, depending on context

In Brazilian Portuguese, if you want to make it very clear that the action is happening at this moment, estar + gerund is the most natural choice.

So if you hear the cat at this moment, O gato está miando is the best option.

Miando is the gerund of the verb miar, which means to meow.

For -ar verbs, the gerund is usually formed by replacing -ar with -ando:

• falar → falando
• estudar → estudando
• miar → miando

So miando means meowing.

The accent in está shows the stressed syllable and helps distinguish pronunciation.

• está is pronounced with stress on the last syllable: es-TÁ

This is the ele/ela/você form of the verb estar in the present tense:

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

The accent is part of the correct spelling.

In Brazilian Portuguese, miando is roughly pronounced like mee-AHN-doo, with the stress on an.

A rough breakdown:

• mi = mee
• an = a nasal sound, not exactly like English an
• do = doo with a light d

So the whole sentence O gato está miando is roughly:

oo GAH-too es-TAH mee-AHN-doo

That said, rough English spellings are only approximations. The nasal sound in miando is especially important to listen to in native audio.

Usually, the normal and most natural order is:

O gato está miando.

That is:

• subject: O gato
• verb phrase: está miando

Portuguese can sometimes change word order for style, emphasis, or in special contexts, but for a learner, this standard order is the safest and most natural.

So if you are simply saying The cat is meowing, stick with O gato está miando.

Yes, it is completely natural in Brazilian Portuguese.

Brazilian Portuguese very commonly uses estar + gerund for actions in progress:

• está chovendo = it is raining
• estou trabalhando = I am working
• o gato está miando = the cat is meowing

In European Portuguese, people often prefer estar a + infinitive instead:

• O gato está a miar

But in Brazil, O gato está miando is the normal everyday form.

Not always. Portuguese often drops subject pronouns like eu, ele, or nós when the verb already makes the subject clear. But with a noun like o gato, you usually include it if you want to say who is doing the action.

For example:

• Está miando. = Is meowing. / It is meowing.
  This can work if the context already makes it obvious that you mean the cat.

• O gato está miando. = The cat is meowing.
  This is clearer and more complete.

So in isolation, keeping O gato is best.