"Calling" a meeting means telling or asking a group of people to have a meeting.
You usually "call" a meeting to talk about something important and unexpected.
Mike called a meeting this morning to tell us about Lana getting fired.
I wanted to call a meeting because we've recently had a bunch of errors slip past us, and we need to make sure that that doesn't happen.
For meetings that are on a regular schedule, you don't use this phrase:
We have a regular meeting every Monday morning.