A senhora prefere esta ou aquela?

Yes. In this sentence, a senhora is a formal way to say you when speaking to a woman.

Literally, senhora means lady or madam, so a senhora can also mean the lady in other contexts. But when talking directly to someone, it often functions as a respectful you.

So this sentence is grammatically built with a senhora, but in meaning it corresponds to formal you.

Because Portuguese normally uses the definite article with many nouns and titles when they are part of the sentence.

So a senhora is the full noun phrase. This is very natural in Portuguese:

• A senhora prefere...
• O senhor quer...

If you are directly calling the person, you may hear Senhora without the article, as a form of address:

• Senhora, prefere esta ou aquela?

But in the sentence you were given, a senhora is acting as the subject, so the article is normal.

Because a senhora takes third-person singular verb forms in Portuguese.

That is one of the big things English speakers have to get used to: some forms that mean you are treated grammatically as he/she forms.

So:

• eu prefiro = I prefer
• você prefere = you prefer
• a senhora prefere = you prefer, formally, to a woman
• ele/ela prefere = he/she prefers

That is why the verb is prefere.

Not necessarily, but it is definitely formal and can sound age-marked.

In Brazil, senhora is used to show respect, especially:

• in customer service
• with strangers in formal situations
• with older adults
• when being especially polite

However, some younger women may not love being called senhora, because it can suggest they are older. In everyday casual Brazilian Portuguese, você is much more common.

They are both demonstratives.

In this sentence, they are feminine singular forms, because they refer to an implied feminine noun such as camisa, blusa, bolsa, etc.

The basic traditional contrast is:

• esta = this one
• essa = that one
• aquela = that one over there / that one farther away

So esta ou aquela? is a contrast like this one or that one over there?

This is a very common learner question.

Traditional grammar teaches a three-way distinction:

• este/esta/isto = near the speaker
• esse/essa/isso = near the listener or already mentioned
• aquele/aquela/aquilo = far from both

But in everyday Brazilian Portuguese, the contrast between este and esse is often weaker than textbooks suggest. Many speakers use esse/essa in places where a grammar book might prefer este/esta.

So the sentence A senhora prefere esta ou aquela? is perfectly correct and has a textbook-style contrast. In real life, you may also hear:

• A senhora prefere essa ou aquela?

Because the noun is understood from context.

This works like English this one and that one. Portuguese often leaves the noun out when it is obvious.

For example, if the person is choosing between two dresses, the full idea might be:

• A senhora prefere esta saia ou aquela saia?

But Portuguese naturally shortens that to:

• A senhora prefere esta ou aquela?

The demonstratives still have to match the omitted noun in gender and number.

Because they refer to an implied feminine singular noun.

Portuguese demonstratives agree with the noun they refer to.

Examples:

• feminine singular: esta, essa, aquela
• masculine singular: este, esse, aquele
• feminine plural: estas, essas, aquelas
• masculine plural: estes, esses, aqueles

So if the hidden noun were masculine, you would not say esta ou aquela. You would say something like:

• A senhora prefere este ou aquele?

Usually not in a sentence like this.

Isto and aquilo are neuter demonstratives. They are used when the thing is not identified by a noun, or when you are referring more generally to this thing or that thing.

For example:

• O que é isto? = What is this?
• Aquilo parece caro. = That seems expensive.

But when you are choosing between specific items and the implied noun has gender, Portuguese normally uses forms like:

• esta / essa / aquela
• este / esse / aquele

So here, esta ou aquela? is the natural choice.

The demonstratives would change to match the noun.

Examples:

• masculine singular: A senhora prefere este ou aquele?
• feminine plural: A senhora prefere estas ou aquelas?
• masculine plural: A senhora prefere estes ou aqueles?

If you include the noun, it would look like this:

• A senhora prefere esta blusa ou aquela?
• A senhora prefere este vestido ou aquele?

Yes, absolutely.

Você prefere esta ou aquela? is the less formal version and is much more common in everyday Brazilian Portuguese.

Both você and a senhora take the same verb form:

• você prefere
• a senhora prefere

The difference is mainly politeness and formality, not verb conjugation.

It is just the normal order:

subject + verb + option A + ou + option B

So:

• A senhora = subject
• prefere = verb
• esta = first option
• ou = or
• aquela = second option

Portuguese often forms simple questions with the same word order as statements, using intonation and question marks rather than changing the structure.

So this matches normal spoken Portuguese very well.