Magistra dicit hoc nomen in numero singulari esse.

Magistra is the subject of the main verb dicit. It is nominative singular feminine and means the female teacher or simply teacher.

A useful reminder for English speakers: Latin has no articles, so magistra can mean the teacher or a teacher depending on context.

Dicit is the 3rd person singular present active indicative of dicere, meaning to say.

So magistra dicit means the teacher says.

Because hoc has to agree with nomen in gender, number, and case.

• nomen is neuter
• it is singular
• here it is functioning as accusative singular in an indirect statement

The neuter singular form of hic, haec, hoc is hoc, so hoc nomen is the correct agreement.

It is accusative singular here.

That can be confusing, because for many neuter singular words, the nominative and accusative forms are identical. So:

• hoc can be nominative or accusative neuter singular
• nomen can be nominative or accusative singular

In this sentence, hoc nomen is the subject of the infinitive esse, and in Latin indirect statement that subject goes into the accusative.

Because after a verb like dicit, Latin normally uses an indirect statement construction:

• verb of saying/thinking/perceiving
• plus accusative subject
• plus infinitive

So instead of saying something like the teacher says that this noun is... with a finite verb like est, Latin says:

• magistra dicit
• hoc nomen = accusative subject
• esse = infinitive

This is often called the accusative-and-infinitive construction.

Because Classical Latin usually does not use a word like English that after verbs of saying in this kind of sentence.

English says:

• The teacher says that this noun is in the singular number.

Latin usually says:

• The teacher says this noun to be in the singular number.

That sounds unnatural in normal English, but it reflects the Latin structure. The idea of that is built into the accusative + infinitive construction, so no extra word is needed.

Both numero and singulari are ablative singular.

That is because they follow in, and here in takes the ablative. Also:

• numero is the noun
• singulari is an adjective modifying numero
• so they must agree in case, number, and gender

So:

• in numero singulari = in the singular number

This is a grammatical expression referring to singular number.

Because singulari has to agree with numero.

The dictionary form of the adjective is singularis, singulare, but adjectives change form depending on their job in the sentence. Since numero is ablative singular masculine, the adjective must also be ablative singular masculine:

• dictionary form: singularis
• form used here: singulari

So in numero singulari is grammatically matched.

Nomen is a 3rd-declension neuter noun.

Its basic forms are:

• nomen = nominative singular
• nominis = genitive singular

A learner may expect a word meaning name or noun to be masculine or feminine, but in Latin nomen is neuter. That is why words agreeing with it, like hoc, also appear in neuter forms.

Because Latin word order is much more flexible than English word order. The infinitive in an indirect statement often comes near the end, so esse at the end is very natural.

Latin could rearrange the sentence in other ways and still keep the basic meaning, but this order is clear and idiomatic:

• Magistra sets up the speaker
• dicit introduces the statement
• hoc nomen gives the accusative subject
• in numero singulari esse completes the indirect statement

So the final esse is normal Latin style, not something strange or emphatic by itself.