A vízóra működik.

In Hungarian, a is the definite article, so here it means the, not English a/an.

• a is used before consonant sounds
• az is used before vowel sounds

So:

• a vízóra = the water meter
• az óra = the clock / the meter

Hungarian does not have a separate word exactly matching English a/an in the same way this sentence uses a.

Because vízóra starts with v, which is a consonant.

Hungarian definite articles change form depending on the next word:

• a
  • consonant: a vízóra
• az
  • vowel: az autó

So az vízóra would be incorrect.

Yes. Vízóra is a compound noun in Hungarian.

It is made up of:

• víz = water
• óra = clock, watch, meter

In compounds like this, óra can mean a meter/gauge, not just a clock. So vízóra means water meter.

This is very common in Hungarian. For example:

• gázóra = gas meter
• villanyóra = electricity meter

That is a very natural question. In Hungarian, óra often means clock or watch, but in certain compounds it also means a measuring device or meter.

So in everyday usage:

• karóra = wristwatch
• falióra = wall clock
• vízóra = water meter
• gázóra = gas meter

You can think of óra in these compounds as something like a device with a dial/display that measures something.

Működik is:

• present tense
• third person singular
• from the verb működni = to work, to function, to operate

So:

• én működöm = I function / I work
• te működsz = you function
• ő működik = he/she/it functions

Here the subject is a vízóra, which is singular, so működik is the correct form.

It can mean either, depending on context.

Hungarian present tense often covers both:

• works
• is working
• functions
• operates

So A vízóra működik. could mean:

• The water meter works.
• The water meter is working.
• The water meter is functioning.

English chooses between these more explicitly than Hungarian often does.

Because működik already contains the full verbal idea: works / functions / operates.

This is not a sentence like The water meter is broken, where English uses is plus an adjective. Here, Hungarian uses a normal lexical verb:

• működik = works/functions

So no separate is is needed.

It is in the nominative form, with no case ending.

This is the basic dictionary form of the noun, used here as the subject of the sentence.

• vízóra = the water meter
• a vízóra működik = the water meter works

If it were in another case, it would take an ending. For example:

• vízórát = water meter (object form)
• vízórán = on the water meter

But in this sentence, no ending is needed.

Yes. Hungarian word order is flexible, and changing it often changes the focus or emphasis, not just the basic meaning.

The neutral sentence is:

• A vízóra működik.

This is a plain statement: The water meter works.

You could also say:

• Működik a vízóra.

This can sound more like:

• The water meter does work
• The water meter is working
• or it may emphasize the fact that it works, perhaps in contrast with something else

So the original order is the most neutral one for a simple statement.

You say:

• A vízóra nem működik.

Here nem is the standard word for not.

So:

• működik = works
• nem működik = does not work / isn’t working

In Hungarian, nem usually comes directly before the verb.

A rough pronunciation guide:

• vízóra ≈ VEE-zoh-rah
• működik ≈ MUE-kuh-dik

A few important points:

• í and ó are long vowels
• ű and ö/ő are front rounded vowels, which do not exist in standard English
• stress in Hungarian normally falls on the first syllable of each word

So the stress is:

• VÍ-zó-ra
• MŰ-kö-dik

Also, Hungarian spelling is quite regular, so once you learn the sounds, pronunciation becomes much easier.

The dictionary form is működni, which means to work, to function, or to operate.

In vocabulary lists, Hungarian verbs are usually given in the infinitive, often ending in -ni:

• működni = to function
• beszélni = to speak
• menni = to go

In the sentence, that infinitive changes to the conjugated form működik.

Yes, it is completely natural.

A vízóra működik. is a normal, straightforward sentence. A Hungarian speaker would understand it as a simple factual statement that the water meter is functioning properly.

In real life, depending on context, people might also say things like:

• A vízóra rendben működik. = The water meter is working properly.
• A vízóra nem működik. = The water meter isn’t working.

But your sentence itself is perfectly normal.