Στο ταχυδρομείο αγόρασα ένα γραμματόσημο και έστειλα ένα μικρό δέμα στη γιαγιά μου.

Στο is a contraction of σε + το.

• σε = in, at, to
• το = the (neuter singular)

So στο ταχυδρομείο literally means at the post office or in the post office. In this sentence, at the post office is the most natural translation.

This contraction is extremely common in Greek:

• σε + το = στο
• σε + τη(ν) = στη(ν)
• σε + τον = στον

So Στο ταχυδρομείο is just the normal way to say at the post office.

Greek word order is more flexible than English word order.

In English, we usually say:

• I bought a stamp at the post office...

But in Greek, it is very natural to begin with the place:

• Στο ταχυδρομείο αγόρασα...

This puts a little emphasis on where the action happened. It is not strange or poetic; it is completely normal Greek.

A more neutral English-like order would also be possible in Greek:

• Αγόρασα ένα γραμματόσημο στο ταχυδρομείο...

Both are correct, but the given sentence highlights the location first.

ταχυδρομείο means post office.

It is a neuter noun, which is why it uses the article το in its basic form:

• το ταχυδρομείο = the post office

In the sentence, after σε, it becomes:

• στο ταχυδρομείο = at the post office

Also notice that many Greek nouns ending in -είο are neuter.

Both αγόρασα and έστειλα are in the aorist, which is the main Greek tense used for a completed action in the past.

• αγόρασα = I bought
• έστειλα = I sent / I mailed

The aorist here presents the actions as simple completed events:

• I bought a stamp.
• I sent a small package.

This is the normal tense for narrating single past actions.

Because Greek verbs usually already show the subject.

• αγόρασα already means I bought
• έστειλα already means I sent

So Greek does not need to say εγώ (I) unless the speaker wants emphasis or contrast.

For example:

• Εγώ αγόρασα... = I bought...
  This sounds more like I bought it / I was the one who bought it.

In your sentence, no special emphasis is needed, so the subject is simply understood from the verb ending.

ένα means a / an here.

Both γραμματόσημο (stamp) and δέμα (package, parcel) are neuter singular nouns, and ένα is the neuter singular form of the indefinite article.

So:

• ένα γραμματόσημο = a stamp
• ένα μικρό δέμα = a small package

Greek articles and adjectives change form depending on gender, number, and case, so ένα is used because these nouns are neuter singular.

μικρό means small, and it matches δέμα.

Since δέμα is:

• neuter
• singular
• here functioning as the direct object

the adjective also takes the matching neuter singular form:

• ένα μικρό δέμα = a small package

This matching is called agreement. In Greek, adjectives agree with the noun they describe in gender, number, and case.

Compare:

• μικρός for a masculine noun
• μικρή for a feminine noun
• μικρό for a neuter noun

Yes. They are in the accusative case, because they are the direct objects of the verbs.

• αγόρασα ένα γραμματόσημο = I bought a stamp
• έστειλα ένα μικρό δέμα = I sent a small package

However, for many neuter singular nouns, the nominative and accusative forms are the same. So even though they are accusative here, they look unchanged.

That is why you see:

• ένα γραμματόσημο
• ένα μικρό δέμα

without any obvious ending change.

στη is a contraction of σε + τη(ν).

• σε = to, at, in
• τη(ν) = the (feminine singular)

So:

• στη γιαγιά μου = to my grandmother

In this sentence, στη expresses the recipient of the package, so it means to.

Just like στο, this contraction is standard modern Greek:

• στη = σε τη
• στην = σε την

In everyday writing and speech, στη is very common.

Because Greek normally uses σε for an indirect object like to my grandmother.

English can say:

• I sent my grandmother a package
• I sent a package to my grandmother

Greek typically expresses this with σε:

• έστειλα ένα δέμα στη γιαγιά μου

So στη γιαγιά μου literally means to my grandmother.

Without σε, τη γιαγιά μου would usually be understood as a direct object:

• είδα τη γιαγιά μου = I saw my grandmother

So the στη is important because it shows that grandmother is the recipient, not the thing being sent.

Yes, μου means my here.

Greek often uses a weak possessive form placed after the noun:

• η γιαγιά μου = my grandmother
• το βιβλίο μου = my book

So:

• στη γιαγιά μου = to my grandmother

This may feel backwards to an English speaker, but it is completely normal in Greek. The little word μου is also related to me, so literally it comes from the same set of forms as personal pronouns.

Yes. και means and, and Greek commonly joins two completed actions this way:

• αγόρασα ένα γραμματόσημο και έστειλα ένα μικρό δέμα
• I bought a stamp and sent a small package

This is a very natural way to narrate a sequence of actions in Greek. Both verbs are in the same tense, and the subject is understood to be the same person for both verbs.

It can mean either, depending on context.

The verb στέλνω / έστειλα basically means send. In a post-office context, English often translates it as mail:

• έστειλα ένα μικρό δέμα = I sent a small package
• or more naturally in context: I mailed a small package

So both are fine. Sent is the more literal translation; mailed is often the more idiomatic one in this specific situation.

A rough pronunciation guide is:

Sto tachydromEEo agorasa ENa grammatOSimo ke ESTila ENa mikRO DHEma sti yaYA mu.

A few helpful notes:

• χ in ταχυδρομείο is like the h/ch sound in Scottish loch or German Bach
• γιαγιά sounds roughly like ya-YA
• δέμα has a soft th/dh sound at the start, like th in this
• The written accent mark shows which syllable is stressed:
  • ταχυδρομείο
  • αγόρασα
  • γραμματόσημο
  • μικρό
  • γιαγιά

You do not need a perfect English approximation, but the stress patterns are very important in Greek.

In theory, σε can mean to, in, or at, depending on context. But in this sentence, Στο ταχυδρομείο is naturally understood as at the post office.

Why?

Because the actions happen there:

• I bought a stamp
• I sent a small package

So the phrase gives the location where these actions took place.

If someone wanted to emphasize movement to the post office, Greek would usually make that clearer from the wider context or by using a different structure. Here, at the post office is the correct reading.