Ήταν μια περίεργη σύμπτωση.

Ήταν is the past form of είμαι (to be). In this sentence it means was.

More specifically, it is the imperfect form. Greek uses the imperfect of είμαι very often where English simply says was/were.

A useful point: ήταν can mean I was, you were, he was, she was, it was, we were, they were depending on context. Here, because the sentence is impersonal, English translates it as it was.

Greek often does not use an explicit subject pronoun when it is not needed.

So English It was a strange coincidence becomes simply:

Ήταν μια περίεργη σύμπτωση.

Greek does this very naturally. The idea of it is understood from the situation, so adding a separate pronoun would usually be unnecessary.

Μια means a / one here.

It is used because σύμπτωση is a feminine singular noun, and the indefinite article must match it.

Greek indefinite articles:

• ένας = a, one for masculine nouns
• μια / μία = a, one for feminine nouns
• ένα = a, one for neuter nouns

Since σύμπτωση is feminine, we use μια.

Yes, but it is small.

Both μια and μία mean a / one for feminine nouns.

• μια is extremely common in everyday writing and speech.
• μία is a slightly more careful or formal spelling, and it can also help when you want to stress the idea of one.

So in this sentence, μια περίεργη σύμπτωση is completely natural.

Because it is an adjective agreeing with a feminine singular noun.

The noun σύμπτωση is feminine singular, so the adjective must also be feminine singular:

• masculine: περίεργος
• feminine: περίεργη
• neuter: περίεργο

So:

• περίεργος άνθρωπος = a strange man
• περίεργη σύμπτωση = a strange coincidence
• περίεργο πράγμα = a strange thing

This matching is called agreement.

One clue is its ending: many Greek nouns ending in -η or -ση / -ωση are feminine.

σύμπτωση is a feminine noun, so it takes:

• feminine article: μια
• feminine adjective: περίεργη

You will often learn noun gender together with the article:

• η σύμπτωση = the coincidence

That is the safest habit: learn nouns as η σύμπτωση, not just σύμπτωση by itself.

A rough pronunciation is:

EE-tan mia pe-RYEHR-ghee SOOM-pto-see

A slightly more careful guide:

• Ήταν ≈ EE-tan
• μια ≈ mya
• περίεργη ≈ pe-REE-er-ghee
• σύμπτωση ≈ SEEM-pto-see or SOOM-pto-see, depending on how you approximate Greek sounds in English

A few sound notes:

• η, ι, υ, ει, οι are all pronounced like ee in modern Greek.
• γ before η/ι/ε/αι sounds like a soft sound somewhat like y in some contexts, but in περίεργη English speakers often approximate it as gh/y.
• μπτ in σύμπτωση can feel tricky; say it slowly at first: sym-pto-si.

The accent mark in Greek shows which syllable is stressed.

So:

• Ήταν → stress on the first syllable
• περίεργη → stress on ρί
• σύμπτωση → stress on σύμ

Stress matters in Greek pronunciation, so the written accent is important.

A rough stress pattern for the whole sentence is:

Ήταν μια περίεργη σύμπτωση

Yes, Greek word order is more flexible than English.

The most neutral order here is:

Ήταν μια περίεργη σύμπτωση.

But you could also hear or read:

• Μια περίεργη σύμπτωση ήταν.
• Περίεργη σύμπτωση ήταν.

These alternatives can sound more marked or stylistic, depending on context. For a learner, the original sentence is the safest and most natural basic pattern.

Usually, μια is the most natural choice here.

Ήταν μια περίεργη σύμπτωση sounds like normal Greek for It was a strange coincidence.

If you remove μια and say Ήταν περίεργη σύμπτωση, it may sound less standard or more compressed/stylistic, depending on context. For everyday learning, keep the article.

It can cover several related meanings, depending on context.

περίεργος / περίεργη / περίεργο can mean:

• strange
• odd
• weird
• sometimes curious

In this sentence, strange or odd is probably the best natural English equivalent:

• It was a strange coincidence.

So the adjective is broad, and context tells you the best translation.

Yes.

Because Greek often drops subject pronouns, ήταν can mean both was and were, depending on the subject and context.

Examples:

• Ήταν κουρασμένος. = He was tired.
• Ήταν κουρασμένοι. = They were tired.
• Ήταν μια περίεργη σύμπτωση. = It was a strange coincidence.

So you do not decide the English subject only from ήταν by itself; you decide from the whole sentence.

The structure is:

Ήταν + μια περίεργη σύμπτωση
= was + a strange coincidence

So grammatically it is:

• verb: Ήταν
• noun phrase: μια περίεργη σύμπτωση

Inside the noun phrase:

• μια = indefinite article
• περίεργη = adjective
• σύμπτωση = noun

This is a very common Greek pattern and a useful one to remember.