answer the door
To open a door after someone has knocked on it or pressed a doorbell. Can you answer the door? I'm a little busy right now. I did knock, but no one answered the door.
answer the door
Fig. [after hearing the doorbell or a knock] to go to the door to see who is there. Would you please answer the door. I am busy. I wish someone would answer the door. I can't stand to hear the knocking.