おかわり (okawari) means “second helping, another helping”

More examples

給食をおかわりします。kyū shoku o o ka wa ri shi ma su

I get another helping of school lunch.

おかずをおかわりしたいです。o ka zu o o ka wa ri shi ta i de su

I would like a second helping of the side dishes.

Centers on getting an additional serving that continues the same meal rather than starting a separate order.

追加tsuika: An extra amount or item added to what is already provided.

同じ食事や飲み物を、さらにもう一度もらうこと。ona ji shoku ji ya no mi mono o sa ra ni mō ichi do mo ra u ko to

The noun おかわり (okawari) consists of お (o, "polite prefix") and 代わり (kawari, "replacement"), a noun related to 代わる (kawaru, "to replace").

A server may ask おかわりは？ (okawari wa?) as a short question, leaving the food or drink being offered understood from context.