Ο πατέρας μου δουλεύει σε μεγάλη εταιρεία.

My father works at a big company.

Breakdown of Ο πατέρας μου δουλεύει σε μεγάλη εταιρεία.

• μου: my
• δουλεύω: to work
• μεγάλος: big
• σε: in

Questions & Answers about Ο πατέρας μου δουλεύει σε μεγάλη εταιρεία.

What does Ο mean at the beginning of the sentence, and why is it written that way?

Ο is the definite article in Greek, meaning “the”.
Here it is:

• masculine
• singular
• nominative case

It is used because πατέρας (father) is masculine singular in the nominative, so they must match: Ο πατέρας = “the father”.

It’s written with a capital Ο because it is the first word of the sentence. In the middle of a sentence it would be ο (lowercase).

Why is it πατέρας and not something like πατήρ that I sometimes see?

Πατέρας is the normal modern Greek word for “father” in everyday speech and writing.

Πατήρ is an older, more formal/ancient form, which you might see:

• in very formal or religious language
• in older texts or certain fixed expressions

For regular, modern conversation, you use πατέρας.

What exactly does μου mean, and why does it come after πατέρας instead of before like “my father”?