The criteria of parve food (that can be eaten with either meat or cheese) are of fundamental importance in the kosher home.
The principles underlying the halachot of parve food also have vast ramifications for eating outside the home when preparing food in a non-kosher kitchen while on holiday and when eating in a non-kosher restaurant (at a business meeting for example).
In short, how can a non-kosher kitchen be prepared for kosher cooking (as in a holiday rental) and what can be eaten in a non-kosher restaurant?
As usual, sources are available through the links.