Latarka czołowa jest w plecaku.

Because latarka czołowa is a normal Polish noun phrase: a noun plus an adjective.

• latarka = flashlight / torch
• czołowa = head-mounted, forehead-related

So latarka czołowa literally means something like forehead flashlight, i.e. headlamp / head torch.

In everyday Polish, people also very often say czołówka, which is a shorter, more colloquial word for the same thing.

In Polish, adjectives usually come after or before nouns depending on style and type, but with ordinary descriptive adjectives, the most neutral order is often:

• adjective + noun in dictionary-style phrases
• but many established expressions also commonly appear as noun + adjective

Here, latarka czołowa is a very natural fixed phrase. You may also hear czołowa latarka much less often, but latarka czołowa is the standard way to name the object.

Also, czołowa must agree with latarka:

• latarka is feminine singular
• so the adjective is also feminine singular: czołowa

It is in the nominative singular.

That is because it is the subject of the sentence:

• Latarka czołowa = the thing being talked about
• jest = is
• w plecaku = in the backpack

Both words are nominative singular:

• latarka
• czołowa

Jest is the 3rd person singular form of być (to be), so it means is.

In this sentence, it links the subject to its location:

• Latarka czołowa jest w plecaku.
• The headlamp is in the backpack.

Polish often drops to be in some kinds of sentences, especially in informal speech or in sentences like To mój brat. But in a normal full sentence expressing location, jest is very natural and standard.

You might see Latarka czołowa w plecaku in a note, checklist, or very casual style, but the full grammatical sentence is Latarka czołowa jest w plecaku.

Because the preposition w changes case depending on meaning.

Here it means in / inside, so it takes the locative case.

• dictionary form: plecak
• after w for location: w plecaku

So:

• w plecaku = in the backpack

If w expresses movement into something, then it usually takes the accusative instead:

• Wkładam latarkę w plecak.
• I put the flashlight into the backpack.

So the key difference is:

• w + locative = location
• w + accusative = movement into

Because plecak is a masculine noun, and in the locative singular many masculine nouns take the ending -u or -ie.

Here:

• plecak → w plecaku

This is something learners mostly need to memorize noun by noun, although patterns do exist.

A few similar examples:

• dom → w domu
• pokoj → w pokoju
• bank → w banku

So plecaku is simply the correct locative singular form after w when it means in.

Polish has no articles, so there is no direct equivalent of a/an or the.

So Latarka czołowa jest w plecaku could be understood as:

• The headlamp is in the backpack
• A headlamp is in the backpack

In real context, the listener figures it out from the situation. Very often, English translations use the if the item is already known or specific.

Yes. Polish word order is fairly flexible, and changing it often changes emphasis, not the core meaning.

For example:

• Latarka czołowa jest w plecaku.
  Neutral: talking about the headlamp and saying where it is.

• W plecaku jest latarka czołowa.
  Focuses more on what is in the backpack.

• Jest w plecaku latarka czołowa.
  Possible, but less neutral and more context-dependent.

So the original sentence is a very normal neutral order.

Yes. W here means in / inside.

So w plecaku means the headlamp is inside the backpack.

If you wanted to say it was on the backpack, you would use a different preposition, for example:

• na plecaku = on the backpack

That distinction is important:

• w plecaku = inside
• na plecaku = on the surface of / attached to

Yes. Czołowa comes from czoło, which means forehead.

That is why latarka czołowa refers to a lamp worn on the head/forehead area.

This is a useful word family to notice:

• czoło = forehead
• czołowy / czołowa / czołowe = frontal, front, leading, forehead-related depending on context

So in this phrase, czołowa means something like head-mounted or forehead-worn.

A rough pronunciation guide is:

la-TAR-ka cho-WO-va yest f ple-TSA-ku

A few notes:

• ł sounds like English w
• cz sounds like ch in chop
• w sounds like English v
• j sounds like English y
• c sounds like ts

So:

• latarka ≈ la-TAR-ka
• czołowa ≈ cho-WO-va
• jest ≈ yest
• w plecaku ≈ f ple-TSA-ku

The w before plecaku is often pronounced more like f because of the following voiceless consonant.