Paul s’encorde avec le nœud en huit et le baudrier.

S’encorde is the verb s’encorder, used here in the third person singular: Paul s’encorde = Paul ropes himself in / ties himself in.

It is a reflexive verb, which means it uses a reflexive pronoun:

• je m’encorde
• tu t’encordes
• il / elle s’encorde
• nous nous encordons
• vous vous encordez
• ils / elles s’encordent

The s’ refers back to Paul. So grammatically, Paul is performing the action on himself.

In French, se becomes s’ before a vowel sound for easier pronunciation.

So:

• se encorde → s’encorde

This is called elision. You see the same thing in many other verbs:

• s’appeler
• s’habiller
• s’entraîner

Without the reflexive pronoun, encorder would usually mean something like to tie/rope someone or something.

But s’encorder means to rope oneself up / tie oneself in.

So the reflexive pronoun is important:

• Paul encorde quelqu’un = Paul ropes someone in
• Paul s’encorde = Paul ropes himself in

French often uses the definite article (le, la, les) where English might use a, the, or sometimes no article at all.

Here, le nœud en huit and le baudrier refer to the standard equipment or method being used, not necessarily to something already mentioned in the conversation.

So French naturally says:

• avec le nœud en huit et le baudrier

Even if English might sometimes say:

• with a figure-eight knot and a harness

This use of the definite article is very common when talking about tools, body parts, clothing, or standard procedures.

Literally, nœud means knot and en huit means in eight.

So un nœud en huit is literally a knot in the shape of an 8, which corresponds to the English figure-eight knot.

In French, en often means in the form of or shaped like:

• plié en deux = folded in two
• coupé en rondelles = cut into slices
• un nœud en huit = a figure-eight knot

Because both nouns are part of the same with phrase.

So:

• avec le nœud en huit et le baudrier

means:

• with the figure-eight knot and the harness

French, like English, does not need to repeat the preposition before the second noun if both are linked together.

Compare:

• Il écrit avec un stylo et du papier.
• Elle vient avec Paul et Marie.

You could repeat avec for emphasis or clarity in some contexts, but it is not necessary here.

French uses en in many expressions that describe shape, form, or transformation.

So en huit means in the form of an eight.

That is why nœud en huit is the normal expression. Using à huit or de huit here would sound unnatural.

Le baudrier is a harness, especially in climbing or mountaineering.

It is a more specific word than a general belt or strap. In this sentence, the context is clearly climbing equipment:

• le nœud en huit
• le baudrier
• s’encorder

So even if the meaning is already known, it helps to notice that this is specialized vocabulary from climbing.

Nœud is pronounced roughly like the French sound neud, with the vowel œu, which does not exist exactly in English.

A simple learner-friendly approximation is something like:

• nuh with rounded lips or
• similar to the vowel in French peur or sœur

Important points:

• the n is pronounced
• the œu is one vowel sound
• the final d is usually silent

So nœud is one syllable.

No. These are two completely different things.

In s’encorde, the en is simply part of the verb encorder / s’encorder. It is not a separate word.

In nœud en huit, en is a preposition meaning something like in the shape of.

So even though both contain en, they have different functions:

• s’encorde → verb form
• en huit → prepositional phrase

Because the subject is Paul, which is third person singular.

So the correct present-tense form is:

• je m’encorde
• tu t’encordes
• il s’encorde

Since Paul = he, we use s’encorde.

Yes. French often has more than one natural way to express the same basic idea.

For example, in climbing contexts you might also see wording such as:

• Paul s’encorde avec un nœud en huit.
• Paul s’attache au baudrier avec un nœud en huit.
• Paul s’encorde sur son baudrier avec un nœud en huit.

The exact wording depends on what the speaker wants to emphasize: the action of roping in, the knot, or the harness.

But the original sentence is grammatically understandable and clearly built around climbing vocabulary.