La clau anglesa és entre el pedal i el pinyó.

Because clau is a feminine noun in Catalan: la clau.
Adjectives must agree with the noun they describe, so you get:

• anglès = masculine singular
• anglesa = feminine singular

So la clau anglesa is grammatically feminine all the way through.

A useful lesson here is that noun gender in Catalan is not always obvious from the ending. Even though clau does not end in -a, it is still feminine, so it is best to learn nouns together with their article: la clau, el pedal, el pinyó.

Because in Catalan, adjectives often come after the noun. That is the normal position in many cases, especially with descriptive adjectives and many fixed expressions.

So:

• clau anglesa = literally English wrench/key
• not usually anglesa clau

For an English speaker, this is one of the most common word-order differences to get used to.

Literally, yes, the words are:

• clau = key / wrench
• anglesa = English

But together clau anglesa is a set expression meaning adjustable wrench or adjustable spanner.

So you should learn clau anglesa as a single vocabulary item, not as a word-for-word phrase about something from England.

In Catalan, ser is very commonly used for location, much more than an English speaker might expect if they also know Spanish.

So a neutral sentence like:

• La clau anglesa és entre el pedal i el pinyó.

is perfectly normal.

In other words, Catalan often says is with ser for simple location:

• On és la clau? = Where is the wrench/key?

An English speaker who knows Spanish may expect estar, but in standard Catalan ser is often the default choice for telling where something is.

The accent in és helps distinguish it from es, which is a different word.

• és = is
• es = a pronoun, as in reflexive/passive constructions

So the accent is important in writing because it tells you that this is the verb to be.

This is the standard Catalan pattern for between X and Y:

• entre = between
• i = and

So:

• entre el pedal i el pinyó = between the pedal and the sprocket/cog

If you are building the phrase yourself, think:

• entre + noun phrase + i + noun phrase

That pattern is very straightforward and matches English quite closely.

Because Catalan normally uses definite articles with specific nouns:

• el pedal
• el pinyó

So entre el pedal i el pinyó sounds natural when you mean a specific pedal and a specific sprocket/cog.

English sometimes uses fewer articles or handles them differently, but in Catalan it is normal to keep them here.

Also, the articles tell you the gender:

• el pedal = masculine singular
• el pinyó = masculine singular

A rough guide:

• clau sounds roughly like clow, rhyming with now
• pinyó sounds roughly like pee-NYO

The important thing in pinyó is ny:

• ny is like the ñ sound in Spanish
• or like the ny in English canyon

The accent in pinyó shows that the stress falls on the last syllable:

• pi-nyó

So the stressed part is -nyó.

The sentence is:

• La clau anglesa = subject
• és = verb
• entre el pedal i el pinyó = location phrase

So the full structure is basically:

subject + verb + location

That is very close to English. The main differences for an English learner are:

• adjective after the noun: clau anglesa
• Catalan article usage: la / el
• Catalan using ser naturally for location here