La policía paró la pelea.

Because it is the third-person singular preterite form of parar: él/ella paró = he/she/it stopped.

The accent matters because paro without an accent is a different form and can mean:

• I stop (from parar)
• unemployment
• strike

So paró and paro are not the same word.

The accent also shows the stress:

• paró → pa-RÓ
• paro → PA-ro

It is the preterite tense, also called the simple past.

Here, paró means that the action is seen as completed:

• La policía paró la pelea = the police stopped the fight.

The full pattern for parar in the preterite is:

• paré = I stopped
• paraste = you stopped
• paró = he/she/it stopped
• paramos = we stopped
• parasteis = you all stopped
• pararon = they stopped

In Spanish, la policía is often treated as a singular collective noun when it means the police force or the police as an institution.

So Spanish says:

• La policía paró la pelea.

Even though English uses the police with a plural verb, Spanish commonly uses la policía with a singular verb.

If you want to talk about individual officers, you can say:

• Los policías pararon la pelea = the police officers stopped the fight

Yes, it can.

Policía is a noun that can refer to:

• el policía = the male police officer
• la policía = the female police officer
• la policía = the police force / the police

So by itself, la policía can be ambiguous.

In this sentence, if the meaning shown to the learner is the police stopped the fight, then la policía is being understood as the police force, not a female police officer.

Context normally makes this clear.

Because la pelea means the fight, not a fight.

Spanish uses the definite article here because the fight is being treated as specific or known from context.

Compare:

• La policía paró la pelea = the police stopped the fight
• La policía paró una pelea = the police stopped a fight

So the article changes how specific the noun sounds.

Because the personal a is mainly used before specific people (and sometimes pets or personified beings), not before things or events.

Here, la pelea is a fight, not a person, so no personal a is needed.

Compare:

• La policía paró la pelea = the police stopped the fight
• La policía paró a un hombre = the police stopped a man

Yes, that is possible.

Both parar and detener can mean to stop. In this sentence:

• paró la pelea sounds natural and straightforward
• detuvo la pelea is also understandable, and can sound a bit more formal or forceful

Very often, detener is also used for stopping people, vehicles, or arrests:

• La policía detuvo al sospechoso = the police detained/arrested the suspect

So paró is a very natural choice here for stopping a fight.

Because it follows the normal, neutral Spanish order:

subject + verb + object

• La policía = subject
• paró = verb
• la pelea = direct object

This is the most standard way to say it.

Spanish can change word order for emphasis, but this version is the plain, unmarked one:

• La pelea la paró la policía would be more emphatic or marked

For a learner, La policía paró la pelea is the basic model to remember.

It is pronounced roughly pe-LE-a, with three syllables.

The stress is on the middle syllable:

• pe-LE-a

This happens because the vowels are pronounced separately at the end:

• -ea is not collapsed into one syllable here

So it sounds something like:

• peh-LEH-ah

Because the sentence describes a completed action: the police stopped the fight.

The preterite:

• paró = stopped, as a finished event

The imperfect:

• paraba = was stopping / used to stop

So:

• La policía paró la pelea = the police stopped the fight
• La policía paraba las peleas = the police used to stop fights / was stopping fights

The preterite is the normal choice for a single finished event like this.

Yes.

In Spanish from Spain, the present perfect is often used for recent past actions, especially when the time period is connected to the present.

So depending on context, you might hear:

• La policía paró la pelea
• La policía ha parado la pelea

Very roughly:

• paró presents it as a completed past event
• ha parado can sound more connected to now or to a recent situation

Both are possible in Spain, but the sentence you were given uses the simple past paró.