De onde vem esse cheiro de pipoca? Acho que é da praça de alimentação.

Onde means where.
De onde means from where.

In this sentence, the speaker is asking about the source of the smell, not just its location. That is why Portuguese uses de:

De onde vem esse cheiro? = Where does this smell come from?

If you used only onde, you would be asking where it is, not where it comes from.

That word order is very natural in Portuguese, especially in questions introduced by words like onde, quando, como, por que, and de onde.

So De onde vem esse cheiro? is a very normal structure.

You may also hear De onde esse cheiro vem? in speech, and it is understandable, but De onde vem esse cheiro? sounds more standard and very natural.

Vem comes from the irregular verb vir, which means to come.

Here, vem is the third-person singular present form, because the subject is esse cheiro, which is singular.

A few useful forms of vir are:

• eu venho = I come
• você/ele/ela vem = you/he/she comes
• nós vimos = we come
• vocês/eles/elas vêm = you/they come

Notice the difference between:

• vem = singular
• vêm = plural

In many Brazilian Portuguese textbooks, you learn a distinction like this:

• este = this, near the speaker
• esse = that, near the listener
• aquele = that over there

But in real spoken Brazilian Portuguese, the distinction between este and esse is often much weaker, and esse is extremely common in everyday speech.

So esse cheiro sounds very natural in Brazil.
Este cheiro is possible, but it can sound more formal or less conversational.

Cheiro de pipoca describes the type of smell: a popcorn smell.

Portuguese often uses de + noun to describe what something is like, made of, or associated with:

• cheiro de café = smell of coffee
• gosto de chocolate = taste of chocolate
• suco de laranja = orange juice

Cheiro da pipoca would usually mean the smell of the popcorn, referring to some specific popcorn already identified in the conversation.

So in this sentence, cheiro de pipoca is the natural general expression.

In Portuguese, pipoca is usually treated as a general food noun, much like popcorn in English.

So cheiro de pipoca means the smell of popcorn in a general sense.

You can use pipocas in some contexts, but pipoca is the normal choice when talking about popcorn as a substance or food in general.

Acho que means I think (that).

It comes from the verb achar, which can mean to think, to find, or to consider, depending on context.

• acho = I think
• que = that

So literally, Acho que é da praça de alimentação is I think that it’s from the food court.

In English, you can often omit that, but in Portuguese, que is normally kept in this structure.

Both are possible.

• Acho que é da praça de alimentação = I think it’s from the food court
• Acho que vem da praça de alimentação = I think it’s coming from the food court

The version with é da is shorter and very natural. Portuguese often uses ser de to indicate origin or source.

In the second sentence, é refers back to esse cheiro. So the idea is:

Acho que esse cheiro é da praça de alimentação.

The noun esse cheiro is simply not repeated.

Because the idea is source, not location.

• de / da = from
• em / na = in / at

So:

• É da praça de alimentação = It’s from the food court
• Está na praça de alimentação = It’s in the food court

Since the speaker is guessing where the smell is coming from, da is the correct choice.

Da is a contraction of:

de + a = da

This happens very often in Portuguese.

Some common contractions are:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

So:

da praça de alimentação = from the food court

The noun praça is feminine, so it takes a, and that is why you get da.

Praça de alimentação is the normal Brazilian Portuguese term for a food court.

You hear it especially for the eating area in places like:

• shopping malls
• airports
• universities
• large commercial centers

Literally, the words look like plaza of food/eating, but as a set expression, it simply means food court.

Cheiro is usually neutral or pleasant, depending on context. It can mean smell or scent.

So cheiro de pipoca sounds natural because popcorn usually has a pleasant smell.

For a bad smell, Portuguese often uses:

• mau cheiro = bad smell
• fedor = stink

So in this sentence, cheiro works well because the smell is being identified, not criticized.