noun
bowl
BOHL/bəʊl/
A deep rounded container or hollow.
The deep ceramic bowl holds soup.

Etymology
Bolla named a pot or cup as well as a bowl. The English word also once meant a large drinking cup, illustrating its longstanding connection with containers for food and drink.
In context
Basically we're going to put the potatoes and the onions into a bowl lined with a cheesecloth, and then squeeze the liquid out of both.