1
general::
Phrase(s): enter (up)on something
1. to come in at a particular point as marked by something. • We entered the theater upon the most delicate point of the story. • We entered on the tail end of a live scene. 2. to begin something. • Todd entered upon a new phase of his life. • He entered on the management of a new project.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, enter upon. Set out, begin, as in We are entering on a new era, or They entered upon the most difficult part of the research. [Early 1600s]
American Heritage Idioms