Multi-activity courses are divided into lecture, recitation and/or a laboratory.
Lectures are typically led by a professor and take place in a large group. They are often, but not always, divided into subgroups called recitations that typically meet once each week in smaller groups for discussions.
Each of these "activities" has its own section code. Only one part of a multi-activity course actually carries the credit. When registering for such a course, the credit-bearing portion must be requested first, and students must be sure to register for all parts.
If a course has several lecture sections, the recitation needs to correspond to the appropriate lecture. Each lecture may be grouped with a specific set of recitations. Students must register for a lecture/recitation within the same group.