Differences between "fortification nouns"

Differences between "fortification nouns"

What are the practical differences between these nouns?
Fort
Fortress
Fortification
Stronghold
Citadel
Castle
Palace
Context
In Norway we have a lot of old stone buildings, typically built for war in
the 1600s. Most of the their names are translated to English using
fortress, but, sometimes, one of the other nouns are used.
I have looked up these words in different dictionaries, but I haven't been
able to determine the differences between them. When is it appropriate to
choose one over the other?