Quintus liber longus est.

The fifth book is long.

Breakdown of Quintus liber longus est.

• esse: to be
• liber: the book
• longus: long
• quintus: fifth

Questions & Answers about Quintus liber longus est.

What kind of word is quintus here?

Here quintus is an ordinal adjective, meaning fifth. It describes liber, so the phrase means the fifth book or book five, depending on context.

Latin ordinal numbers work like adjectives, so they change form to match the noun they go with.

Could Quintus here be a person’s name instead?

In other sentences, yes: Quintus can be a Roman male name.

But in this sentence, it is understood as fifth, not as a name. A very common beginner mistake is to think Quintus liber means Quintus’s book, but that is not how Latin shows possession.

To say Quintus’s book, Latin would normally use the genitive: Quintī liber or liber Quintī

So Quintus liber does not mean Quintus’s book.

Why do quintus and longus both end in -us?

Because both are masculine nominative singular adjectives.

They match liber, which is also masculine nominative singular. In Latin, adjectives must agree with the noun they describe in:

• gender
• number
• case

So:

• quintus matches liber