Na bundě je jeden vlas.

Because na is expressing a location here, and with location na takes the locative case.

• basic form: bunda = jacket
• after na for location: na bundě = on the jacket

So:

• Na bundě = on the jacket

This is a very common pattern in Czech:

• na stole = on the table
• na zdi = on the wall
• na bundě = on the jacket

In this sentence, na means on, because it shows that something is located on the surface of something else.

So:

• na bundě = on the jacket

Czech na can have several meanings depending on context, but one of its most common uses is exactly this: on / onto.

A useful contrast is:

• na bundě = on the jacket
• v bundě = in the jacket

Here, since a hair is lying on the outside surface, na is the natural choice.

Je is the 3rd person singular form of být = to be.

So the sentence is literally structured like:

• Na bundě = on the jacket
• je = is
• jeden vlas = one hair

Czech often uses to be in sentences of existence or location, just as English does in There is one hair on the jacket or One hair is on the jacket.

Because vlas is singular, the verb is also singular: je.

Both are possible, but they mean slightly different things in emphasis.

• Na bundě je vlas. = There is a hair on the jacket.
• Na bundě je jeden vlas. = There is one hair on the jacket.

Adding jeden makes the number explicit. It can sound like the speaker is noticing that there is exactly one.

So jeden is the masculine form of one, agreeing with vlas.

Because vlas is a masculine inanimate noun in the nominative singular, and jeden has to agree with it.

• jeden vlas = one hair

Czech numbers like one behave a lot like adjectives in this respect: they change form to match gender and case.

For comparison:

• jeden vlas = one hair
• jedna bunda = one jacket
• jedno auto = one car

Here vlas is masculine, so the correct form is jeden.

Vlas usually means a single strand of hair.

That is important because English hair can be:

• uncountable: There is hair everywhere
• countable in some contexts: a hair

Czech makes this distinction more clearly:

• vlas = one hair, one strand
• vlasy = hair as a mass / hairs collectively / head hair

So in this sentence, jeden vlas means one strand of hair.

Sometimes yes, depending on what kind of hair is meant.

• vlas usually refers to human hair, especially a strand from someone’s head
• chlup usually means an animal hair, body hair, or a coarse hair/fur

So if someone sees a human hair on a jacket, vlas is the normal word.

Czech word order is much more flexible than English word order. The sentence often starts with what is already known or what sets the scene.

So:

• Na bundě je jeden vlas. = On the jacket, there is one hair.
• Jeden vlas je na bundě. = One hair is on the jacket.

Both are grammatically possible, but Na bundě je jeden vlas sounds more natural if you are first pointing out the location and then introducing what is there.

This is very common in Czech: location first, then the thing that exists there.

Not necessarily. Czech does not have articles like a and the, so bunda does not automatically tell you whether it is a jacket or the jacket.

That information comes from context.

So Na bundě je jeden vlas could mean:

• There is one hair on the jacket
• There is one hair on a jacket

In real use, context tells you which one is meant.

A simple learner-friendly pronunciation is:

na BOON-dye ye YE-den vlas

A few helpful details:

• na sounds like nah
• bu in bundě sounds like boo
• dě is a soft syllable, roughly like dye
• je sounds like ye
• jeden sounds roughly YE-den
• vlas sounds close to vlahs

The letter j in Czech is pronounced like English y in yes, so:

• je = ye
• jeden = yeden

No, in standard Czech you normally keep the present-tense form of být in this kind of sentence.

So:

• Na bundě je jeden vlas. = correct

Leaving out je would sound ungrammatical in standard Czech.

Czech does omit to be in some very limited styles or special constructions, but not in an ordinary sentence like this one.