This is the 7761st most frequent Dutch word.
dien
"Dien" means "to serve" in English.
Here, "dien" is part of the phrase "in dienst" which means "in service of" and is used to describe the function or purpose of the action.
Hij heeft een portefeuille, in dienst van zijn werk.
He has a portfolio in service of his work.
In this case, "dien" takes the form of a verb indicating service or fulfillment of duties based on legal contexts.
De wet bepaalt bepalingen, waarop wij moeten dien.
The law sets provisions upon which we must serve.
Here, "dienen" is used as a verb meaning "to serve" or "to assist" a purpose, in this case related to comprehension.