A maioria esperou no prédio.

In Portuguese, maioria is normally used as a noun, so it usually takes an article: a maioria. English often says most without an article, but Portuguese prefers a maioria for the majority / most people.

So for a learner, a maioria is the natural basic form to remember.

Because a maioria is grammatically singular. The main noun is maioria, so the verb usually agrees with that singular noun:

A maioria esperou.

Even though the meaning involves several people, Portuguese often treats collective expressions like this as singular. For learners, singular agreement is the safest and most standard choice.

Esperou is the 3rd person singular of esperar in the pretérito perfeito simples.

Here it presents the action as a completed event in the past. In other words, the waiting happened and is viewed as finished.

Compare:

• esperou = waited, did wait
• esperava = was waiting, used to wait

The difference is aspect:

• esperou shows the action as a complete past event
• esperava shows an ongoing, repeated, or background action in the past

So:

• A maioria esperou no prédio = the action is seen as completed
• A maioria esperava no prédio = the majority was waiting in the building / used to wait in the building

Both are possible Portuguese, but they do not mean exactly the same thing.

Yes. Esperar can mean to wait, to expect, and sometimes to hope, depending on context.

In this sentence, because of no prédio, the meaning is clearly to wait.

For example:

• Esperei no prédio. = I waited in the building.
• Espero o autocarro. = I am waiting for the bus.
• Espero que ele venha. = I hope he comes.

So the verb itself is flexible; the context tells you which meaning is intended.

Portuguese often leaves out subject pronouns when they are not needed. The verb form already gives enough grammatical information, and the subject is explicitly stated as a maioria.

So A maioria esperou is perfectly normal. Adding a pronoun would usually be unnecessary here.

No is a contraction of em + o:

• em = in, at, on
• o prédio = the building
• em + o prédio → no prédio

This kind of contraction is very common in Portuguese:

• na = em + a
• nos = em + os
• nas = em + as

No prédio means in the building / in the specific building. It usually refers to a building that is already known from the context.

Num prédio means in a building / in one building, so it is less specific.

Compare:

• A maioria esperou no prédio. = in the building
• A maioria esperou num prédio. = in a building

So the choice depends on whether the building is specific or not.

In European Portuguese, prédio is a very common everyday word for building, especially a multi-storey building such as a block of flats or a larger urban building.

It can overlap with edifício, but edifício often sounds a bit more formal or technical. In normal speech, prédio is extremely common.

So for a learner of Portuguese from Portugal, prédio is a very useful everyday word.

Most naturally, no prédio means in the building or inside the building.

English sometimes uses at where Portuguese prefers em / no, so a direct word-for-word match is not always perfect. If you want to be clearly outside or by the building, Portuguese would often say something more specific, such as:

• à porta do prédio = at the door of the building
• junto ao prédio = next to / by the building

So in this sentence, no prédio is best understood as in the building.

Yes, and in European Portuguese estar à espera is a very common way to say to be waiting.

But the meaning changes slightly:

• A maioria esperou no prédio = the majority waited in the building, seen as a completed event
• A maioria estava à espera no prédio = the majority was waiting in the building, seen as ongoing at that moment

So both are correct, but they express different time/aspect nuances.

The stress falls on the first syllable: PRÉ-dio.

For an English speaker learning European Portuguese, two useful points are:

• the stressed vowel in pré- is an open é
• the ending -dio is not pronounced like English dee-oh; it is more compact

You do not need to pronounce every letter in a strongly English way. The most important thing is to stress PRÉ- correctly.