gate
The word 'porte' in French is used to describe a barrier or a movable structure controlling access through an opening in a wall, fence or outside; similar to how 'gate' is used in English. It's commonly used in both context of regular conversations, and literary usage.
I close the door
This sentence uses the word 'porte' as a noun to refer to a door. It is used in the context of closing a door, which is a common action.
Where is the door?
This sentence uses 'porte' in the context of a question. It is asking for the location of a door. This form is common in French when asking about the location of objects.