Nuotiopaikka on suljettu.

Nuotiopaikka is a compound noun:

• nuotio = campfire
• paikka = place, spot, site

So literally it is campfire place/site.

Finnish makes a lot of compound words, much more freely than English does. Where English often uses two words, Finnish often uses one. So nuotiopaikka is the normal way to say campfire site / fire pit area / designated fire place.

A useful rule:

• in Finnish compounds, the last part is the main word
• the earlier part describes it

So nuotiopaikka is a kind of paikka.

Finnish does not have articles like the or a/an.

So Nuotiopaikka on suljettu can mean:

• The campfire site is closed
• A campfire site is closed

In real life, context usually makes it clear which one is meant. In a sign or notice, English would normally use The campfire site is closed or simply Campfire site closed.

On is the 3rd person singular present form of olla, which means to be.

So:

• minä olen = I am
• sinä olet = you are
• hän on = he/she is
• se on = it is

Here the subject nuotiopaikka is singular, so Finnish uses on = is.

Suljettu comes from the verb sulkea, which means to close.

In this sentence, suljettu means closed.

It is the form commonly used when something is in a closed state:

• Kauppa on suljettu. = The shop is closed.
• Tie on suljettu. = The road is closed.
• Nuotiopaikka on suljettu. = The campfire site is closed.

So if you see on + suljettu, it very often corresponds to English is closed.

It is originally a participle form of the verb sulkea, but in sentences like this it behaves very much like an adjective.

That is why learners often understand it best as closed.

So grammatically, you can think of it like this:

• on = the actual finite verb (is)
• suljettu = a participle used as a predicate adjective-like word (closed)

You do not need to worry too much about the label at first. The important practical pattern is:

• X on suljettu = X is closed

Usually, in everyday context, it is best understood as is closed.

So:

• Nuotiopaikka on suljettu. = The campfire site is closed.

However, because suljettu comes from a verb, the sentence can also carry the idea that the place has been closed and is now in that state. In other words, it often describes a resulting state.

English usually just says is closed unless the action itself is the main point.

Here nuotiopaikka is in the nominative singular, which is the basic dictionary form.

That is the normal form for the subject of a sentence:

• Nuotiopaikka = the campfire site
• Nuotiopaikka on suljettu. = The campfire site is closed.

If the word changed role in the sentence, its case could change:

• nuotiopaikan = of the campfire site / the campfire site as an object in some contexts
• nuotiopaikalla = at the campfire site
• nuotiopaikasta = from the campfire site / about the campfire site

But in your sentence, the basic subject form nuotiopaikka is exactly what you expect.

Because the subject is singular, the predicate word appears in the singular basic form here:

• Nuotiopaikka on suljettu. = The campfire site is closed.

If the subject were plural, Finnish would normally use a plural form:

• Nuotiopaikat ovat suljettuja. = The campfire sites are closed.

So this is a useful comparison:

• singular: on suljettu
• plural: ovat suljettuja

Also, Finnish does not have grammatical gender, so there is no masculine/feminine agreement to worry about.

You make it negative with ei ole:

• Nuotiopaikka ei ole suljettu. = The campfire site is not closed.

That is the normal pattern:

• on → ei ole

Examples:

• Kauppa on suljettu. = The shop is closed.
• Kauppa ei ole suljettu. = The shop is not closed.

A very common way is to add -ko/-kö to the verb:

• Onko nuotiopaikka suljettu? = Is the campfire site closed?

This is one of the most useful Finnish question patterns:

• Onko kauppa auki? = Is the shop open?
• Onko tie suljettu? = Is the road closed?

So:

• statement: Nuotiopaikka on suljettu.
• question: Onko nuotiopaikka suljettu?

Sometimes, yes, but the nuance is a little different.

• kiinni often means shut or closed in the sense of not open
• suljettu often sounds more official or like something has been formally closed

For example:

• Kauppa on kiinni. = The shop is closed.
• Tie on suljettu. = The road is closed.
• Nuotiopaikka on suljettu. = The campfire site is closed.

With a place like a campfire site, suljettu is very natural because it can imply an official restriction: maybe because of fire risk, maintenance, or regulations.

Very roughly for an English speaker:

• nuotiopaikka ≈ NUO-ti-o-PAIK-ka
• on ≈ on
• suljettu ≈ SUL-yet-tu

A few useful pronunciation points:

• Finnish stress is usually on the first syllable:
  NUO-tio-paikka, SUL-jettu
• Double letters are important:
  • kk in paikka
  • tt in suljettu
• The j in Finnish sounds like English y in yes

You do not need a perfect accent at first, but it helps to notice that Finnish spelling is very regular: words are usually pronounced much the way they are written.