L'arnès és nou.

L' is the shortened form of the definite article el before a vowel sound.

• el arnés becomes l'arnès
• This is called elision

So L'arnès means the harness.

Arnès means harness. It can refer to:

• a safety harness
• an animal harness
• other types of harness depending on context

It is a normal Catalan noun, though not one of the most basic everyday words for beginners.

It is masculine.

You can tell from the article:

• l'arnès = the harness
• if it were feminine, it would also look like l' before a vowel, so the article alone does not always show gender clearly

But the adjective helps here:

• nou is the masculine singular form of new

So L'arnès és nou shows that arnès is masculine singular.

Because arnès is masculine singular, the adjective must agree with it.

The adjective nou changes like this:

• nou = masculine singular
• nova = feminine singular
• nous = masculine plural
• noves = feminine plural

So:

• L'arnès és nou = The harness is new
• La corretja és nova = The strap is new

The accent mark in arnès shows where the stress falls.

• arnès is stressed on the last syllable: ar-NÈS

In Catalan, written accents often help you know the correct pronunciation and sometimes distinguish between words.

És has an accent to distinguish it from es.

• és = is
• es = a reflexive or pronoun form, depending on context

So the accent is important because it changes the meaning.

És is the third person singular form of the verb ser.

So:

• ser = to be
• és = is

In this sentence, it links the subject to a description:

• L'arnès = the harness
• és = is
• nou = new

Catalan, like Spanish, often distinguishes between ser and estar.

Here, ser is used because nou describes an inherent or identifying quality of the object:

• L'arnès és nou = The harness is new

This is not usually seen as a temporary state, so ser is the natural choice.

Yes, in this sentence the word order is very similar to English:

• L'arnès = the harness
• és = is
• nou = new

So it follows the pattern:

• subject + verb + adjective

That makes this sentence quite straightforward for English speakers.

A simple learner-friendly pronunciation guide would be:

• L'arnès ≈ lar-NESS
• és ≈ ess
• nou ≈ noh or now said more smoothly, depending on accent

A more important point than exact English spelling is the stress:

• l'ar-NÈS
• ÉS
• NOU

Catalan pronunciation varies somewhat by region, but that stress pattern stays important.

Yes, nou can also mean nine, but not here.

Catalan nou has two different meanings depending on context:

• nou = new
• nou = nine

In L'arnès és nou, it clearly means new because it is functioning as an adjective describing arnès.

The plural would be:

• Els arnesos són nous. = The harnesses are new.

Changes:

• l'arnès → els arnesos
• és → són
• nou → nous

This shows agreement in both the noun phrase and the adjective.

Normally, no, if you mean the harness.

• L'arnès és nou = The harness is new

If you remove the article, it usually sounds incomplete or changes the meaning. Catalan generally uses the definite article in places where English also uses the.