Το κλείστρο λειτουργεί καλά.

Το is the definite article, meaning the.

In this sentence, το goes with κλείστρο, so το κλείστρο = the shutter / the bolt / the latch, depending on context.

Greek articles change for gender, number, and case, so you cannot use just one word for the in all situations.

Here, το is the neuter singular form.

Κλείστρο is a neuter noun.

A very common clue is the ending -ο: many Greek nouns ending in -ο are neuter, and they usually take the article το in the singular:

• το βιβλίο = the book
• το παιδί = the child
• το κλείστρο = the shutter / latch / bolt

So το κλείστρο is a normal neuter noun phrase.

Here it is in the nominative, because it is the subject of the sentence: it is the thing that functions / works.

So the structure is:

• Το κλείστρο = the subject
• λειτουργεί = works / functions
• καλά = well

A useful note: for many neuter nouns, the nominative and accusative singular look the same, so το κλείστρο could be either in another sentence. In this one, the meaning and sentence structure show that it is the subject.

Λειτουργεί comes from the verb λειτουργώ, which means to function, to operate, or to work in the sense of working properly.

So:

• λειτουργώ = I function / I work
• λειτουργείς = you function / you work
• λειτουργεί = he/she/it functions, works

In this sentence, κλείστρο is singular, so the verb is also third person singular: λειτουργεί.

The accent matters in Greek and must be written correctly: λειτουργεί.

This verb belongs to the common modern pattern in -ώ:

• λειτουργώ
• λειτουργείς
• λειτουργεί

The accent shows where the stress falls. Without the accent mark, the spelling would be incorrect in normal Greek writing.

Also, the ending -εί here is pronounced like ee.

A rough pronunciation guide is:

to KLEE-stro lee-tour-GHEE ka-LA

A few details:

• κλείστρο → stress on κλεί-
• λειτουργεί → stress on the last syllable, -γεί
• καλά → stress on the last syllable, -λά

A few sound notes for English speakers:

• ει is pronounced like ee
• γ before ε/ι sounds like a soft Greek sound that does not exist exactly in English; in learner-friendly terms, you can start with something like gh/y depending on accent and speed
• στρ in κλείστρο is a real consonant cluster, so say it tightly: KLEE-stro

Yes, here λειτουργεί means works, but specifically in the sense of:

• functions
• operates properly
• is in working order

So it is used for things like:

• machines
• devices
• systems
• mechanisms
• parts

It usually does not mean works in the sense of has a job. For that, Greek normally uses other expressions, such as δουλεύω for a person working.

So in this sentence, λειτουργεί is a very natural choice for an object or mechanism.

Because καλά here is an adverb, meaning well.

It describes how the shutter/bolt works:

• λειτουργεί καλά = it works well

By contrast, καλό is usually the neuter singular adjective form of καλός:

• καλό κλείστρο = a good shutter / a good bolt

So compare:

• Το κλείστρο είναι καλό. = The shutter is good.
• Το κλείστρο λειτουργεί καλά. = The shutter works well.

That is an important difference:

• adjective: describes a noun
• adverb: describes a verb

Very often, yes, καλά means well as an adverb:

• Μιλάει καλά ελληνικά. = He/She speaks Greek well.
• Λειτουργεί καλά. = It works well.

But in everyday Greek, καλά can also appear in other conversational uses, such as:

• Καλά; = Really? / Wait, what?
• Καλά είμαι. = I’m fine.

So the word is common and flexible, but in Το κλείστρο λειτουργεί καλά, it is clearly the adverb well.

Yes. Greek word order is often more flexible than English, because endings and articles help show what each word is doing.

The neutral, straightforward order here is:

• Το κλείστρο λειτουργεί καλά.

But you could also hear:

• Λειτουργεί καλά το κλείστρο.
• Καλά λειτουργεί το κλείστρο.

These can sound slightly different in emphasis, but the basic meaning stays the same.

For a learner, the given order is the safest and most natural one to produce first.

It depends on the context.

Κλείστρο is a real Greek word, but it can sound a bit technical or specialized, depending on what object is being discussed. It may refer to a mechanical closing part such as a:

• latch
• bolt
• shutter
• breech mechanism
• closure component

So a learner may not meet it as early or as often as very common household nouns. Still, the grammar of the sentence is completely ordinary:

• article + noun
• verb
• adverb

Because Greek verbs already show the person and number.

Λειτουργεί means:

• he/she/it works
• functions

So Greek often does not need to state the subject pronoun unless there is special emphasis or contrast.

And in this sentence, the subject is not a pronoun anyway; it is explicitly named:

• Το κλείστρο λειτουργεί καλά.

So Greek does not need anything like:

• It, the shutter, works well

That would be unnecessary.

Yes, often you could.

Depending on context, λειτουργεί can be translated as:

• works
• functions
• operates

For example:

• Το σύστημα λειτουργεί. = The system works / is operating.
• Η μηχανή λειτουργεί καλά. = The machine operates well / works well.

So the best English translation depends on what κλείστρο refers to in the wider context. The Greek itself is natural either way.

It is a very simple and useful pattern:

subject + verb + adverb

Here:

• Το κλείστρο = subject
• λειτουργεί = verb
• καλά = adverb

You can build many similar Greek sentences with the same pattern:

• Το αυτοκίνητο λειτουργεί καλά. = The car works well.
• Η συσκευή λειτουργεί σωστά. = The device functions correctly.
• Το σύστημα λειτουργεί τέλεια. = The system works perfectly.

So this sentence is a good model for talking about whether something is functioning properly.