Podpalovač je u roštu.

Because u requires the genitive case in Czech.

The dictionary form is rošt. After u, it changes to roštu:

• rošt = base form
• u roštu = by/at the grate

This is a very common Czech pattern: a preposition determines the case of the noun that follows it.

Here u means by, near, or at.

So u roštu means the thing is located next to the grate, not necessarily on it or inside it.

This is broader than a single English preposition, so depending on context, the best translation could be by the grate, at the grate, or near the grate.

Because na and u express different kinds of location.

• u roštu = by/at the grate
• na roštu = on the grate

So if something is physically resting on top of the grate, na would make more sense. If it is just next to it, u is the right choice.

je is the 3rd person singular present form of být, which means to be.

So here it simply means is.

• já jsem = I am
• ty jsi = you are
• on/ona/ono je = he/she/it is

In this sentence, je connects the subject with its location.

Here podpalovač is in the nominative singular because it is the subject of the sentence.

The basic structure is:

• podpalovač = subject
• je = verb
• u roštu = location

So the sentence is built very much like a simple English X is at Y sentence.

Because Czech does not use articles.

So the same sentence can mean:

• A firelighter is by the grate
• The firelighter is by the grate

Context tells you which meaning is intended. This is normal in Czech and is one of the biggest differences from English.

Both are masculine nouns.

That matters because Czech noun gender affects:

• case endings
• adjective agreement
• sometimes pronouns

In this sentence, you mainly see it in the declined form roštu, though the key reason for that ending is the genitive after u.

No, Czech word order is fairly flexible.

Podpalovač je u roštu. is a neutral, straightforward order. But you could also say:

• U roštu je podpalovač.

That version puts more emphasis on the location, as if answering Where is the firelighter?

So the meaning stays very similar, but the focus changes.

A practical learner-friendly approximation is:

• podpalovač ≈ POD-pa-lo-vach
• roštu ≈ ROSH-too

Useful pronunciation points:

• Czech stress is usually on the first syllable.
• š sounds like sh in shoe.
• č sounds like ch in church.
• In normal speech, the d in podpalovač is often pronounced closer to t before p, so it may sound a bit like potpalovač.

Yes. Depending on context, podpalovač can refer to different kinds of fire-starting things or even a person associated with starting fires.

So the exact meaning depends on context, not just on grammar. In this sentence, the intended meaning has to come from the situation or from the translation already given to the learner.

Yes. It is a fully normal, complete Czech sentence.

It has everything it needs:

• a subject: podpalovač
• a verb: je
• a location phrase: u roštu

So for a learner, it is a good example of a basic Czech sentence pattern: subject + být + place.