There are many ways to refer to the same thing. Below is an attempt to demystify our nomenclature:
Events vs. Event Types vs. Time Slots
Events is what you offer people to enroll in. For example, Engineering Bootcamp starting on September 1 in San Francisco is an event.
An event may span multiple days and take place at various places. We call those parts of an event Time Slots. For example, your Bootcamp course may run every day for a week starting with the first time slot on September 1 at 10 AM in Big Conference Room at San Francisco HQ.
You likely run the same type of an event over and over. We call that an Event Type. You can think of an event type as a template or a cookie cutter for your events. In addition to making event creation easier, it provides consistency. For example, Engineering Bootcamp may be a course that runs on a regular basis.
Locations vs. Rooms
A Location is a campus or a building where people can walk to various events. It consists of possibly many rooms where events can take place. Your people use locations to filter for events they can physically walk to. For example, your San Francisco Headquarters may be a location.
Within a location, you have many Rooms. A room could be an arbitrary name that the organizer specifies in the time slot for the event, or it may be an official room name from Google Calendar if Google Resources feature is enabled.