A bowl used for rice (rice bowl) or a bowl/cup used for tea; commonly refers to a rice bowl but can also mean a tea bowl in the tea ceremony.
ご飯はいつも茶碗に盛ります。
I always serve rice in a rice bowl.
茶道では茶碗の扱い方がとても大切だ。
In the tea ceremony, handling the tea bowl carefully is very important.
古い茶碗が割れてしまったので、新しいのを買った。
My old rice bowl broke, so I bought a new one.