Dans cette phrase, le nom est au pluriel.

Because phrase is a feminine singular noun in French.

French demonstratives must agree with the noun:

• ce = masculine singular
• cette = feminine singular
• ces = plural

So:

• cette phrase = this sentence
• but ce livre = this book

Here, nom means noun.

French nom can mean:

• name in everyday language
• noun in grammar

In a grammar sentence like Dans cette phrase, le nom est au pluriel, it clearly means the noun.

If French wants to be extra precise, you may also see nom commun for common noun.

No, because the sentence is talking about one noun in the sentence, and that noun happens to be in the plural form.

So:

• le nom = the noun (singular: one noun being discussed)
• est au pluriel = is in the plural

This is the same idea as in English:

• The word is plural
• The noun is plural

The thing being discussed is singular, even though its grammatical form is plural.

Au is the contraction of à + le.

So:

• à + le = au

Literally, au pluriel is something like in the plural.

This is a very common French grammar expression:

• être au singulier = to be in the singular
• être au pluriel = to be in the plural

So le nom est au pluriel means the noun is in the plural form.

Because être au pluriel is the normal fixed expression in French grammar.

French often uses:

• au singulier
• au pluriel
• au féminin
• au masculin

This structure means something like in the singular/plural/feminine/masculine form.

You may sometimes see adjectives used directly in other contexts, but here au pluriel is the standard and most natural way to say it.

Because le pluriel refers to the grammatical category the plural as a concept.

In au pluriel, French is not counting several plurals. It is naming one category:

• le singulier = the singular
• le pluriel = the plural

So pluriel stays singular.

Dans cette phrase means in this sentence and gives the context for the statement.

Breakdown:

• dans = in
• cette = this
• phrase = sentence

It tells you where the noun appears or what sentence you are talking about.

French often puts this kind of phrase at the start:

• Dans ce texte, ... = In this text, ...
• Dans cet exemple, ... = In this example, ...
• Dans cette phrase, ... = In this sentence, ...

The comma separates the introductory phrase Dans cette phrase from the main statement le nom est au pluriel.

It is similar to English:

• In this sentence, the noun is plural.

The comma is natural because the first part sets the scene, and the second part gives the main information.

A natural pronunciation is approximately:

dahn set fraz, luh non eh oh plu-ree-el

More carefully:

• Dans sounds roughly like dahn
• cette sounds like set
• phrase sounds like fraz
• le nom sounds like luh non
• est au often flows together smoothly
• pluriel sounds roughly like plu-ree-el

There is also natural linking and smooth flow in spoken French, especially around est au.

Yes, absolutely.

That would mean In this sentence, this noun is plural.

The difference is:

• le nom = the noun
• ce nom = this noun

Ce nom points more directly to a specific noun, while le nom sounds a little more general or explanatory.

Very often, yes.

In everyday and grammar contexts:

• une phrase = a sentence

But depending on context, phrase can also mean a phrase in a broader sense, just like in English. In this sentence, though, it clearly means sentence.