Final answer:
A prerequisite is a course that must be taken before enrolling in another course.
Step-by-step explanation:
A course that must be taken before enrolling in another course is called a prerequisite.
A prerequisite is a course or requirement that needs to be completed or achieved before a student can move on to a more advanced or specialized course.
For example, in Mathematics, Algebra I is often a prerequisite for Geometry, and Geometry is a prerequisite for Algebra II.