appetizer; starter; hors d'oeuvre
A small dish served automatically at the beginning of a meal in Japanese restaurants, often before ordering; it is not optional and appears on the bill as a table charge.
When we entered the izakaya, an appetizer was served right away.
This starter is a bit pricey, but it's elaborately prepared.
From the honorific prefix お (o-) and the noun 通し (tōshi), derived from the verb 通す (tōsu, 'to pass through' or 'to let through'), referring to a dish that is served as a matter of course when a customer is seated.