Plumbum grave est.

to be

Breakdown of Plumbum grave est.

• gravis: heavy
• plumbum: lead (the metal)

Questions & Answers about Plumbum grave est.

What case is plumbum, and how do we know it is the subject?

Plumbum is nominative singular here, so it is the subject of the sentence.

A beginner might notice that plumbum could also look like accusative singular, because many neuter second-declension nouns have the same form for nominative and accusative singular. But in this sentence, est means is, and the sentence structure clearly shows plumbum as the thing being described: Lead is heavy.

So:

• plumbum = subject
• grave = predicate adjective
• est = is

Why is the adjective grave and not gravis?

Because plumbum is neuter singular, the adjective has to agree with it.

The dictionary form of the adjective is gravis, grave, meaning heavy. This is a third-declension adjective:

• masculine/feminine nominative singular: gravis
• neuter nominative singular: grave

Since plumbum is a neuter singular noun, Latin uses the neuter singular form of the adjective:

• plumbum grave est = lead is heavy

This is an example of adjective agreement in gender, number, and case.