What does it mean to compromise

Compromising is when both individual parties lose something in order to come to an agreement on one element.

Say I want to have pizza for dinner, but my sister wants to have sausage for dinner, we might argue and talk about it and we would compromise to have a sausage calzone, because we would both get what we want.

A compromise is an agreement or settlement between two parties where each party gets roughly what they want by making concessions.