0 If a period of time or series of events leads up to an event or activity, it happens until that event or activity begins:
The pilot had no recollection of the events leading up to the crash.
1 to prepare to talk about something by gradually mentioning the subject you want to talk about:
2 if a period of time or series of events leads up to an event or activity, it continues until that event or activity begins:
The moments leading up to the accident are very confused in my mind.
What exactly led up to his resignation?
They documented all the events leading up to the massacre.
