A certidão de casamento está no cartório.

No. Here a is the feminine singular definite article, so it means the, not English a/an.

• a certidão = the certificate
• The noun certidão is feminine, so it takes a

In Portuguese, the definite article is used very often, including in many cases where English might also use the.

Certidão usually means an official certificate or official record/document issued by a government office or registry.

In this sentence, certidão de casamento is the official marriage certificate. In Brazil, certidão often refers to legal or civil documents, such as:

• certidão de nascimento = birth certificate
• certidão de óbito = death certificate
• certidão de casamento = marriage certificate

So certidão is not just any certificate; it often has a formal, bureaucratic sense.

Portuguese often uses de + noun to express the idea that English sometimes expresses with another noun used as an adjective.

So:

• certidão de casamento = literally certificate of marriage
• Natural English translation: marriage certificate

This pattern is very common in Portuguese:

• carta de amor = love letter
• sapato de couro = leather shoe
• sala de aula = classroom

So de casamento tells you what kind of certificate it is.

Because the sentence is talking about location, and in Portuguese location is normally expressed with estar, not ser.

• A certidão de casamento está no cartório. = The marriage certificate is at the registry office.

Use estar for where something is:

• O livro está na mesa. = The book is on the table.
• Ela está em casa. = She is at home.

Use ser for identity, classification, origin, time, and other permanent-type descriptions:

• Ela é médica. = She is a doctor.
• Hoje é segunda-feira. = Today is Monday.

So está is used here because the certificate is located somewhere.

No is a contraction of:

• em + o = no

So:

• no cartório = in the / at the registry office

Portuguese commonly contracts em with definite articles:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

Examples:

• no banco = in/at the bank
• na escola = in/at the school
• nos livros = in the books
• nas caixas = in the boxes

So em o cartório is not the normal form; no cartório is.

A cartório is a very Brazilian institution. It is a notary/registry office where important civil and legal records are handled.

Depending on the type of cartório, it may deal with things like:

• births
• marriages
• deaths
• notarized signatures
• property records
• official copies of documents

So in this sentence, cartório is the place where a marriage certificate would normally be kept, issued, or obtained.

A direct English equivalent is tricky. Depending on context, it may be translated as:

• registry office
• civil registry office
• notary office

But cartório has a specifically Brazilian administrative meaning.

It can mean either, depending on how natural the English translation is in context.

Portuguese em often covers both in and at in English.

So:

• está no cartório could be translated as:
  • is in the registry office
  • is at the registry office

In many real situations, at the registry office sounds more natural in English if you are just indicating location generally.

Because grammatical gender in Portuguese is related to noun class, not just meaning.

A useful pattern is:

• many nouns ending in -o are masculine
• many nouns ending in -a are feminine

But this is only a pattern, not a rule that works 100% of the time.

Here:

• o cartório = masculine
• a certidão = feminine

Nouns ending in -ão can be masculine or feminine, so you usually have to learn the article with the noun:

• a certidão
• o avião
• a televisão

A good habit is to memorize nouns together with their article.

A helpful approximation in Brazilian Portuguese is:

• certidão ≈ sehr-chee-DOWN or sehr-ti-DOWN, depending on accent and speed
• cartório ≈ car-TOH-ryoo

A few important pronunciation points:

• ão is a nasal sound. It is not exactly like English ow in down, but that approximation can help at first.
• The stress in certidão is on the last syllable: -dão
• The stress in cartório is on tó

Also, in many Brazilian accents:

• ti before a vowel may sound somewhat like chee So certidão may sound closer to ser-chee-DOWN in everyday speech.

Normally, no. That would sound wrong in standard Portuguese for simple location.

For location, use estar:

• A certidão de casamento está no cartório.

Ser can appear with locations in some specific situations, especially when talking about an event:

• A festa é no salão. = The party is in the hall.
• A reunião é na escola. = The meeting is at the school.

But for the location of an object or document, use estar.

Yes, but it is less neutral.

The normal, neutral order is:

• A certidão de casamento está no cartório.

You can move the location to the front for emphasis or style:

• No cartório está a certidão de casamento.

That might sound literary, formal, or marked, depending on context. In everyday speech, the original version is much more natural.

In this sentence it is singular:

• A certidão de casamento = the marriage certificate

It refers to one specific certificate, probably one already known in the conversation.

If you wanted the plural, you would say:

• As certidões de casamento estão no cartório. = The marriage certificates are at the registry office.

So the sentence as written is about one particular document.

Usually no cartório is the natural choice when talking about the registry office as a specific place.

• está no cartório = is at the registry office

But em cartório also exists in some expressions and can sound more institutional or idiomatic, depending on context. For example, certain legal or administrative phrases may use em cartório.

For a learner, the safest and most natural version in a basic sentence like this is:

• A certidão de casamento está no cartório.