knock on the door of

• knock at the door of

knock on the door of (third-person singular simple present knocks on the door of, present participle knocking on the door of, simple past and past participle knocked on the door of)

1. To ask for entrance or admission into.

   Every year, thousands of students knock on the door of Ivy League universities.

2. Used other than figuratively or idiomatically: see knock,‎ on,‎ the,‎ door,‎ of.

• knocking on heaven's door

• “knock on the door of”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “knock on the door of something”, in Collins English Dictionary.