The indefinite article follows the gender you already know from ο, η and το: ένας for masculine, μία for feminine, ένα for neuter. It is also the number one, and it changes case just as the definite article does.
Examples
- Θα ήθελα μία σαλάτα, παρακαλώ.
- I'd like a salad, please.
- Έναν καφέ, παρακαλώ.
- A coffee, please.
- Είναι ένα πολύ καλό εστιατόριο.
- It's a very good restaurant.
The mistake to avoid
As an object the masculine becomes έναν, with a final -ν: θέλω έναν καφέ.
Where this fits in
Food & ordering, Greek A1: Order at a café or restaurant, ask for the bill, and talk about basic food and drink.