A grelha está quente.

In Portuguese, a can be:

• the feminine singular definite article = the
• or, in other contexts, the preposition to

In A grelha está quente, a is the article the.

That is because grelha is a feminine singular noun, so it takes a:

• a grelha = the grill / the grate

If you wanted a grill in the indefinite sense, you would usually say:

• uma grelha = a grill / a grate

So:

• a = the
• uma = a / an

Yes, grelha is a feminine noun.

You can tell in this sentence because it uses the feminine article a:

• a grelha

Many Portuguese nouns ending in -a are feminine, though that is a pattern, not a perfect rule. The most reliable way is to learn the noun together with its article:

• a grelha

That helps you remember gender naturally.

Grelha can refer to a grill, grate, or grill rack, depending on context.

In Brazilian Portuguese, people may also use related words such as:

• churrasqueira = barbecue grill / barbecue area
• grade = grate, grid, bars
• grelha = the metal grilling surface or grate

So A grelha está quente most naturally means something like:

• The grill is hot
• The grate is hot

The exact English word depends on the situation.

Portuguese has two main verbs for to be:

• ser → used for identity, essence, permanent characteristics
• estar → used for condition, state, location, temporary situation

Here, hot is a current condition, not an essential identity of the grill, so Portuguese uses estar:

• A grelha está quente. = The grill is hot.

Compare:

• A grelha é grande. = The grill is big.
  (describing a characteristic)
• A grelha está quente. = The grill is hot.
  (describing its current state)

The accent mark in está shows the stressed syllable and is part of the correct spelling.

• está = is
• stress falls on the final syllable: es-TÁ

It also helps distinguish it from other forms and keeps the pronunciation clear.

So you should write:

• está

not:

• esta

Because esta without the accent usually means this (feminine):

• esta grelha = this grill

In Brazilian Portuguese, grelha is approximately pronounced:

• GRE-lya

A few helpful notes:

• gr at the start sounds roughly like gr, though the Brazilian r can vary by region
• e here sounds like eh
• lh is a special Portuguese sound, similar to the lli in some pronunciations of million, but smoother
• the final a is usually a light uh/ah sound

A rough guide:

• grelha → GREH-lya

The tricky part for English speakers is lh.

Yes, in Portuguese, adjectives often come after the noun.

So:

• a grelha quente = the hot grill

In your sentence, though, quente is not directly modifying the noun inside a noun phrase. It comes after the verb:

• A grelha está quente.
  literally: The grill is hot.

This is very normal. Portuguese word order here matches English pretty well:

• subject + verb + adjective

Adjectives can sometimes come before nouns in Portuguese, but the usual neutral position is after the noun.

Not in the singular.

Quente has the same form for both masculine and feminine singular nouns:

• o forno está quente = the oven is hot
• a grelha está quente = the grill is hot

In the plural, it becomes:

• quentes

Examples:

• os fornos estão quentes
• as grelhas estão quentes

So the adjective agrees in number, but not visibly in gender here.

In normal Portuguese, that would sound unnatural in most contexts.

Usually you would say:

• A grelha está quente.

Portuguese often uses the definite article where English might or might not use one. Leaving it out can sound incomplete unless you are speaking in a very special style, like headlines, labels, or fragmented notes.

So for standard speech, keep the article:

• a grelha

The plural would be:

• As grelhas estão quentes. = The grills / grates are hot.

Notice all the changes:

• a → as
• grelha → grelhas
• está → estão
• quente → quentes

This is a good example of agreement in Portuguese:

• article agrees with the noun
• verb agrees with the subject
• adjective agrees in number with the noun

Yes. Quente is a very common adjective and can be used in several contexts:

• O café está quente. = The coffee is hot.
• A sopa está quente. = The soup is hot.
• Estou quente. = I’m hot.
• Hoje está quente. = It’s hot today.

So the pattern in your sentence is very useful:

• [thing/person/day] + está + quente

That makes A grelha está quente a good model sentence for many everyday situations.