B1
a large, formal meeting, often lasting a few days, where people discuss their work, politics, subjects they are studying, etc.
Dictionary examples:
The time management conference ran three hours over schedule. (0.0)
At the snoring conference, everyone fell asleep during the keynote speech. (0.0)
At the procrastination conference, nobody showed up until the last day. (0.0)
the annual sales conference (19.5)
They frequently hold conferences at the hotel. (21.8)
I'm speaking at/attending a conference next week. (23.0)
a conference on women's rights (49.6)