be on the threshold of (something)
To be about to do something; to be about to happen. I can't believe that my little girl is actually on the threshold of marriage. I'm confident that our team is on the threshold of a major scientific breakthrough.
on the threshold of (something)
About or likely to happen or do something soon. With the majority of votes having been counted, the candidate is on the threshold of becoming the youngest president in history. We're on the threshold of a major breakthrough in cancer research.
be on the ˈthreshold of something
(formal) be at an important moment when something begins, changes or develops: The country seemed to be on the threshold of war.Now, on the threshold of a new career, he seems confident and happy.The threshold is the floor or ground at the bottom of a doorway, considered as the entrance to a building or room.