Dvouhra není čtyřhra.

In Czech, dvouhra and čtyřhra are singular nouns. They name the type of match or event:

• dvouhra = singles
• čtyřhra = doubles

So Czech treats them more like a singles match and a doubles match, or the singles event and the doubles event, rather than using plural forms the way English does.

That is why the verb is also singular: není = is not.

They are compound words built around hra, which means game or play.

• dvouhra = literally something like two-person game/match
• čtyřhra = literally something like four-person game/match

In actual usage, they mean:

• dvouhra = singles
• čtyřhra = doubles

So the sentence is contrasting two different match formats.

Yes. Very much so.

• dvou- comes from dva / dvě = two
• čtyř- comes from čtyři = four
• hra = game

So these are number-based compounds. You do not normally translate them piece by piece in English, but knowing the parts helps you remember them.

Není is the 3rd person singular form of být (to be) in the present tense, with negation:

• je = is
• není = is not

Since dvouhra is a singular noun, Czech uses the singular verb:

• Dvouhra není čtyřhra. = Singles is not doubles / more naturally, A singles match is not a doubles match.

Because Czech does not have articles.

English needs words like:

• a
• an
• the

Czech usually does not. The meaning is understood from context.

So Dvouhra není čtyřhra can mean things like:

• Singles is not doubles
• A singles match is not a doubles match
• The singles event is not the doubles event

The exact English version depends on context, but Czech does not need separate article words.

Here both are in the nominative singular.

• Dvouhra is the subject.
• čtyřhra is the predicate noun after není.

In sentences with být (to be), Czech commonly uses the nominative for this kind of identification or definition:

• X je Y
• X není Y

So:

• Dvouhra není čtyřhra.

Both nouns happen to look the same in this sentence because they are both nominative singular forms.

Yes, they are feminine singular nouns.

A useful clue is the ending -a, which often marks feminine nouns in Czech. So:

• ta dvouhra
• ta čtyřhra

That said, in this sentence the feminine gender does not change the verb form, because Czech past tense and adjectives show gender more clearly than the present-tense form není does.

A rough learner-friendly pronunciation is:

• dvouhra: DVOU-hra
• není: NE-nee
• čtyřhra: roughly CHTIR-hra or CHTIRZH-hra

A few notes:

• č sounds like ch in church
• ou is a diphthong, somewhat like oh + oo said quickly
• h in Czech is a voiced sound, not exactly like English h
• ř is the famous difficult Czech sound; at first, many learners approximate it with r or rzh

So a practical beginner version is:

DVOU-hra NE-nee CHTIR-hra

That is not perfect, but it is a reasonable start.

This word order is the most neutral one:

• Dvouhra není čtyřhra.

It presents dvouhra as the topic and says what it is not.

You can reverse the nouns:

• Čtyřhra není dvouhra.

That is also correct, but it means Doubles is not singles. The meaning changes because the subject changes.

Czech word order is flexible, but in a simple definition or contrast like this, the standard order is very natural.

No. It is very common in racket sports, especially tennis and badminton, but the words themselves are not limited to tennis.

They refer generally to:

• dvouhra = a one-on-one match format
• čtyřhra = a two-on-two match format

So the sentence can be understood in any relevant sports context where those match types exist.

Because Czech can express the contrast very simply with není:

• Dvouhra není čtyřhra.
• literally: Singles is not doubles.

This is already a clear contrast statement. If needed, Czech could make it more explicit, but it is not necessary here. The basic sentence is short, direct, and idiomatic.