Questions & Answers about Numerus in libro magnus est.
Numerus is a noun meaning number (as in “a number, a quantity,” not the act of numbering).
Grammatically:
- Part of speech: noun
- Gender: masculine
- Number: singular
- Case: nominative
- Role in the sentence: subject
So numerus = the number / a number as the subject of est (is).
In Latin, the subject of a verb is put in the nominative case.
- The verb est means is.
- The thing that is something (the “doer” or the topic of the sentence) is numerus, so numerus must be nominative.
That is why you see numerus, not numerum, numerī, etc.