This is the 363rd most frequent Dutch word.
deur
"Deur" means "door" in English.
Here, 'deur' is used as a noun referring to a physical part of a structure.
De deur is open.
The door is open.
In this sentence, 'deur' again functions as a noun, showing possession or direct object in the action.
Hij sloot zachtjes de deur.
He gently closed the door.
Here, 'deuren' is pluralized from 'deur' and is used metaphorically to signify opportunities.