Ο άγνωστος στο λεωφορείο μου έδωσε τη θέση του.

Yes. άγνωστος is originally an adjective meaning unknown or unfamiliar, but in Greek an adjective can also be used like a noun when it has the article.

So:

• άγνωστος = unknown / unfamiliar
• ο άγνωστος = the unknown man, so in natural English: the stranger

This is very common in Greek. The article helps turn the adjective into a noun-like expression.

Examples:

• ο γνωστός = the acquaintance / the familiar person
• η μικρή = the little girl
• ο φτωχός = the poor man / poor person

So in this sentence, Ο άγνωστος means the stranger.

Greek uses the definite article very often, and much more regularly than English.

Here ο means the, so ο άγνωστος is literally the stranger. In context, Greek often prefers a definite noun phrase where English might sometimes phrase things a little differently.

Also, once a person is being identified in a specific situation — for example, the stranger on the bus — Greek naturally uses the article.

The forms here are:

• ο = masculine singular nominative definite article
• άγνωστος = masculine singular nominative

They match because ο άγνωστος is the subject of the sentence.

στο is a contraction of σε + το.

So:

• σε = in, at, on, to
• το = the
• στο = in the / on the / at the

Therefore:

• στο λεωφορείο = on the bus or literally in the bus

In Greek, σε + definite article is usually written as one word:

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

So στο λεωφορείο is perfectly normal Greek spelling and grammar.

Yes, literally σε often corresponds to in, at, to, or on, depending on context. Greek does not always divide space the same way English does.

With vehicles and places, σε is the normal preposition:

• στο λεωφορείο = on the bus
• στο τρένο = on the train
• στο αυτοκίνητο = in the car
• στο σχολείο = at school
• στο σπίτι = at home / in the house

So even though English says on the bus, Greek uses σε.

It is in the accusative singular, because after the preposition σε, Modern Greek normally uses the accusative.

So:

• το λεωφορείο = the bus
• στο λεωφορείο = on the bus

For this noun, the nominative and accusative singular look the same:

• nominative: το λεωφορείο
• accusative: το λεωφορείο

That is why the form does not visibly change here.

Here μου means to me.

Greek μου can mean either:

• my (possessive)
• to me (indirect object clitic)

In this sentence, it is the indirect object of έδωσε:

• μου έδωσε = gave me

So the structure is:

• Ο άγνωστος = the stranger
• μου έδωσε = gave me
• τη θέση του = his seat

Even though μου can also mean my, here the verb makes it clear that it means to me.

Because μου is a weak object pronoun, often called a clitic, and in Greek these pronouns usually come before the finite verb.

So Greek says:

• μου έδωσε = gave me
• σου είπα = I told you
• του μίλησα = I spoke to him

This is different from English, where me comes after the verb.

A very literal word-for-word order would look like:

• The stranger on the bus to-me gave his seat

That sounds strange in English, but it is normal in Greek.

έδωσε is the aorist (simple past/perfective past) of the verb δίνω = I give.

So:

• δίνω = I give / I am giving
• έδωσα = I gave
• έδωσε = he/she/it gave

In this sentence:

• Ο άγνωστος ... έδωσε = The stranger ... gave

The aorist is used because this is a single completed action: he gave up his seat at that moment.

That έ- is called the augment, a common feature in many past-tense forms in Greek.

For many verbs, the past tense adds ε- at the beginning when the stress pattern requires it.

For example:

• δίνω → έδωσα
• γράφω → έγραψα
• βλέπω → είδα (this one is irregular)

In έδωσε, the augment marks a past form. It is a normal part of the aorist form here.

Because θέση is the direct object of the verb, so it must be in the accusative case, not the nominative.

Compare:

• η θέση = the seat / the position (subject form, nominative)
• τη θέση = the seat / the position (object form, accusative)

In the sentence, what was given?
τη θέση του = his seat

So Greek uses the accusative:

• έδωσε τη θέση του = gave his seat

Both τη and την are common spellings/forms in Modern Greek for the feminine singular accusative article.

• την is the full form
• τη is a very common reduced form before many consonants

So:

• τη θέση
• την θέση

Both can be seen, though τη θέση is extremely normal in everyday writing.

The same thing happens with pronouns too:

• τη βλέπω / την βλέπω = I see her / it

Not always. θέση has a broader meaning: place, position, seat, spot, post, depending on context.

Examples:

• θέση στο λεωφορείο = seat on the bus
• θέση εργασίας = job position
• στη θέση σου = in your place / if I were you
• πάρε θέση = take a position / take your place

In this sentence, because we are talking about a stranger on a bus, τη θέση του naturally means his seat.

Here του means his.

So:

• τη θέση του = his seat

Greek often uses these short possessive forms after the noun:

• το βιβλίο μου = my book
• η τσάντα σου = your bag
• το σπίτι του = his house

So the structure is:

• article + noun + possessive clitic

That is why Greek says:

• τη θέση του instead of putting his before the noun as English does.

Grammatically, του can mean:

• his
• its
• of him
• to him

Its exact meaning depends on context.

But in this sentence, του clearly means his, because it is attached to τη θέση and refers back to ο άγνωστος.

So:

• τη θέση του = his seat

If the owner were female, Greek would say:

• τη θέση της = her seat

They do two different jobs.

• μου = to me → indirect object of the verb
• του = his → possessor of seat

So the sentence breaks down like this:

• Ο άγνωστος = subject
• μου έδωσε = gave me
• τη θέση του = his seat

A useful way to read it is:

• The stranger on the bus gave me [his seat].

So μου belongs with the verb, while του belongs with the noun θέση.

Greek word order is fairly flexible, because the case system and clitic pronouns help show who is doing what.

This sentence could be rearranged in different ways, for example:

• Ο άγνωστος στο λεωφορείο μου έδωσε τη θέση του.
• Μου έδωσε τη θέση του ο άγνωστος στο λεωφορείο.
• Τη θέση του μου έδωσε ο άγνωστος στο λεωφορείο.

These do not all sound equally neutral. The original sentence is a very natural, straightforward version.

Changing the order usually changes emphasis, not the basic meaning.

Yes, that is the most natural interpretation.

Ο άγνωστος στο λεωφορείο means the stranger on the bus — in other words, it identifies which stranger we mean.

So στο λεωφορείο is attached to ο άγνωστος, not mainly to the verb.

It is like saying:

• the stranger on the bus gave me his seat

rather than:

• the stranger gave me his seat on the bus

In practice, the event is obviously also happening there, but grammatically the phrase most naturally identifies the stranger.

Greek often just uses δίνω = give in this context.

So:

• μου έδωσε τη θέση του literally = he gave me his seat
• natural English = he gave me his seat or he gave up his seat for me

English often uses give up one’s seat, but Greek does not need a special phrasal verb here. The meaning is already clear from the object τη θέση του.

Mainly from context.

The phrase τη θέση του by itself could mean:

• his seat
• his place
• his position

But because the sentence includes στο λεωφορείο, the everyday interpretation is very clearly his seat on the bus.

So context does the work here.

You can, but it will sound unnatural in English.

Word-for-word:

• Ο άγνωστος = the stranger
• στο λεωφορείο = on the bus
• μου = to me
• έδωσε = gave
• τη θέση του = his seat

Literal order:

• The stranger on the bus to me gave his seat.

Natural English:

• The stranger on the bus gave me his seat.

So a word-for-word translation is useful for understanding the grammar, but not for producing natural English.