Stojánek, co drží kolo, je vedle blatníku.

Here co means that / which and introduces a relative clause.

So:

• stojánek = the stand
• co drží kolo = that holds the bike / wheel

A more formal version would often use který instead:

Stojánek, který drží kolo, je vedle blatníku.

In everyday speech, co is very common.

In Czech, relative clauses are normally separated by commas. That is different from English, where that holds the bike often has no commas.

So Czech writes:

Stojánek, co drží kolo, je vedle blatníku.

Even if English would not use commas, Czech usually does with this kind of clause.

Yes. Co sounds more conversational and everyday. Který is more standard and is often preferred in careful writing.

So both are understandable, but they feel slightly different:

• stojánek, co drží kolo = everyday, spoken-style
• stojánek, který drží kolo = more formal / standard

It is in the accusative singular, because it is the direct object of drží.

The verb držet usually takes an object in the accusative:

• drží kolo = holds the bike / wheel

With kolo, the nominative and accusative singular look the same, so the form does not change.

Because vedle requires the genitive case.

So:

• dictionary form: blatník
• after vedle: blatníku

That is why the sentence has:

je vedle blatníku = is next to the fender

It can mean either one in Czech. Context decides.

• kolo = wheel
• kolo = bicycle

In this sentence, many learners would understand it as bicycle, especially if stojánek is being understood as a bike stand or kickstand. But depending on the situation, wheel is also possible.

So this is a good example of a Czech word whose exact meaning depends on context.

Yes. It is related to stojan and has a diminutive ending.

But in real usage, that does not always mean it sounds especially cute or emotional. Very often it is simply the normal word for a small stand, and in some contexts it can mean a kickstand.

So although it is technically a diminutive, learners should not always translate it as little stand.

Because the subject is stojánek, which is singular.

The main structure is:

• Stojánek ... je vedle blatníku.
• The stand ... is next to the fender.

The middle part co drží kolo only describes stojánek. It does not change the fact that the main subject is singular.

Czech has no articles like English the and a/an.

So stojánek can mean:

• a stand
• the stand

and the exact meaning comes from context.

That is completely normal in Czech. Learners often want to insert a word for the, but Czech simply does not work that way.

Yes, Czech word order is fairly flexible, although some orders sound more neutral than others.

The original sentence has a neutral structure:

Stojánek, co drží kolo, je vedle blatníku.

You could also move things around for emphasis, for example:

Vedle blatníku je stojánek, co drží kolo.

That version puts more focus on the location vedle blatníku.
So the meaning stays very similar, but the emphasis changes.

Drží is the 3rd person singular form of držet, meaning to hold, to keep, or to support.

So here it means something like:

• holds
• supports
• keeps in place

If the sentence is about a bicycle part, the idea may be that the stand is physically supporting the bike.

A rough English-friendly guide is dr-zhee.

A few points:

• ž sounds like the s in measure
• í is a long ee
• Czech stress is usually on the first syllable of the word

So:

• drží ≈ DR-zhee
• stojánek ≈ STO-yaa-nek
• blatníku ≈ BLAHT-nee-koo

These are only approximations, but they are a useful start.