knock on the door

knock on the door

To present (itself) to one as a possibility in the near future, especially temporarily. Usually refers to opportunities or desirable options. It was hard leaving my parents and all my friends from high school, but when an opportunity to attend school in Europe knocked on the door, I knew I had to seize the chance. What would you do if the chance to make half a million dollars was suddenly knocking on the door?
See also: door, knock, on

knock on (or at) the door

seek to join a particular group or sphere of action.
See also: door, knock, on
References in periodicals archive ?
Her other five children heard the knock on the door but did not answer it because they were taught not to answer the door when their mother is not available.
The court ruled that the agents did not knock on the door as a contrivance to create the exigency, and that it was proper for the agents to pursue their investigation by seeking voluntary cooperation.
This exigency required the police to immediately knock on the door, announce themselves, and ultimately break down the door).
Other courts distinguish cases where the police simply knock on the door and await the suspect's response from those where the police knock on the door and demand the suspect's presence.