Postal codes are what we call an exact classification. We can generally rely on the codes to hold steady. If the postal code is 10012, the building is in Manhattan. There’s nothing to argue about. It just is.
Movie genres like Comedy and Drama may seem exact. But if you put three movie reviewers in a room and ask them to classify a dark comedy into one of those two genres, they may challenge each other.
For example, in editing this book, Nicole suggested I use the term “Postal code” instead of “Zip code” in the example above. Both would have expressed the point, but one is more exact for our context, which includes readers outside of the United States.