Tematické kolo má jednu kategorii.

Because tematické has to agree with kolo.

In Czech, adjectives agree with the noun in:

• gender
• number
• case

Here, kolo is:

• neuter
• singular
• nominative (the subject of the sentence)

So the adjective must also be neuter singular nominative:

• masculine: tematický
• feminine: tematická
• neuter: tematické

So tematické kolo = the thematic round / the themed round.

Yes, kolo can mean wheel, and in everyday language it can also mean bicycle.

But in this sentence, kolo means round, especially in a game, contest, quiz, tournament, or similar activity.

So depending on context, kolo can mean:

• wheel
• bicycle
• round

Here it clearly means round.

Because jednu kategorii is the direct object of the verb má (has), so it has to be in the accusative case.

The dictionary forms are:

• jedna = one
• kategorie = category

But in the accusative singular feminine, they change to:

• jedna → jednu
• kategorie → kategorii

So:

• jedna kategorie = one category as a subject
• má jednu kategorii = has one category as an object

This is one of the most important patterns in Czech: the object often changes form because of case.

No, it is not a typo.

The basic form is kategorie, but in some cases the ending changes to -ii. Here, the accusative singular is kategorii.

So:

• nominative singular: kategorie
• accusative singular: kategorii

This happens with a number of learned or international feminine nouns ending in -ie.

So the double i is just part of the correct declined form.

Má is the 3rd person singular present tense of mít (to have).

The verb mít is conjugated like this in the present tense:

• mám = I have
• máš = you have
• má = he/she/it has

In this sentence, the subject is tematické kolo, which is singular, so the verb must be má:

• Tematické kolo má... = The thematic round has...

Because Czech does not have articles.

English uses:

• a category
• the category

Czech usually just says:

• kategorie

Whether it means a or the depends on context.

So in this sentence, Czech simply says:

• Tematické kolo má jednu kategorii.

There is no separate word corresponding to a or the.

Most naturally, it means one.

Since Czech has no articles, numbers like jeden / jedna / jedno can sometimes feel stronger than English a/an, because they really do express the number one.

So:

• jednu kategorii most naturally = one category

If the speaker chose jednu, they are probably emphasizing that there is exactly one category.

No, Czech word order is more flexible than English word order.

The sentence:

• Tematické kolo má jednu kategorii.

is a very normal, neutral order:

• subject + verb + object

But Czech can move words around to change emphasis. For example:

• Jednu kategorii má tematické kolo.

This still means the same basic thing, but it puts more emphasis on jednu kategorii.

So the original word order is the most neutral and natural, but it is not the only possible one.

A useful rule is that Czech stress is usually on the first syllable of each word.

So the stress pattern is roughly:

• TEmatické
• KOlo
• MÁ
• JEdnu
• KAtegorii

Also, the written accents in Czech mark vowel length, not stress.

For example:

• á and é are long vowels

So in má and the final -ké of tematické, the vowel is long, even though the stress is still at the beginning of the word.

You should definitely pay attention to the cases here, because this sentence is a good example of how important they are in Czech.

What matters most is noticing this pattern:

• subject form: tematické kolo
• object form after má: jednu kategorii

Even if you do not know every case ending yet, this sentence teaches a very useful habit:

• the subject stays in the basic form
• the direct object often changes to the accusative

So yes, you can understand the sentence as a whole first, but it is worth learning jednu kategorii as a clear object pattern.