Learn Romanian: Aveți două locuri acolo.

In Romanian, the number two changes based on the noun's gender: doi is for masculine nouns, and două is for feminine and neuter nouns. The word for seat, loc, is a neuter noun. Because neuter nouns act feminine in the plural, we must use două for "two seats" (două locuri).

Why does the word loc change to locuri in the plural?

Neuter nouns often form their plurals by adding the ending -uri or -e. For loc, the correct plural ending is -uri, making it locuri.

Who exactly is aveți referring to here? Is it plural or singular?

Aveți is the form of the verb a avea (to have) for "you" plural (you all). However, Romanian also uses this exact same plural form to be formal or polite when speaking to just one person. So this could mean "You all have two seats there" or "You (sir/ma'am) have two seats there."

Does locuri always mean "seats"?

Not always. Loc is a very common word that basically means "place", "spot", or "location". In everyday contexts like a train, a cinema, or a restaurant, referring to "two places" translates most naturally to "two seats" in English.