lead up to
phrasal verb
led up to;
leading up to;
leads up to
Definition of lead up to
1
: to occur in the time that comes before (something)
Many voters were still undecided in the days leading up to the election.
2
: to come before and help to cause (something)
There was a series of errors leading up to the accident.
3
: to come before and help to introduce (something)
a chapter leading up to the main topic of the book I had no idea what he was leading up to when he started talking about his father.