Definition · Plain-language
Prerequisite
A prerequisite is a course, qualification or condition that a student must complete before being allowed to enrol in a more advanced course.
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How prerequisites work
Prerequisites appear in the course catalogue beside each class and are enforced at registration: the enrolment system blocks sign-up until the listed condition is met. The requirement may be another course, a minimum grade in that course (for example a C or better), a placement-test score, or class standing such as junior year. Departments set prerequisites to guarantee that everyone entering a course shares a baseline of knowledge, so the instructor can teach at the expected level rather than re-covering material that the syllabus assumes is already understood.
Prerequisite, co-requisite and recommended
A prerequisite must be finished before the course begins. A co-requisite, by contrast, must be taken at the same time — a lecture and its laboratory are a common pairing. A recommended or advisory prerequisite is suggested but not enforced, leaving the choice to the student. Some institutions also list anti-requisites: courses so similar that you may not take both for credit. Reading these labels carefully prevents a registration hold or, worse, being dropped from a class after term has started.
Getting a prerequisite waived
If you already hold the underlying knowledge through transfer credit, a credit-by-examination result, professional experience or an equivalent course taken elsewhere, you can usually request a prerequisite waiver or override from the department or your academic adviser. Approval is at the department’s discretion and often requires documentation. Bypassing a genuine prerequisite without the assumed background is risky: the advanced course will move quickly, and the registrar will not normally protect you from the consequences of an unprepared enrolment.
Key facts
At a glance
- Definition: A requirement completed before enrolling in a more advanced course.
- Enforced by: The registration system, using the course catalogue.
- Common form: A named course, often with a minimum grade.
- Co-requisite: Taken at the same time, not before.
- Waiver: Possible via adviser or department override with evidence.
- Region: US term; UK uses “entry requirements” or “pre-requisites” similarly.
Common misconceptions
What people often get wrong
Often heard: Passing a prerequisite with any grade always lets you continue.
Actually: Many prerequisites require a minimum grade, often a C or better. A bare pass may not satisfy the requirement, so check the exact threshold in the catalogue before assuming you qualify.
Often heard: A prerequisite and a co-requisite are the same thing.
Actually: They differ in timing. A prerequisite must be completed before the course starts; a co-requisite is taken alongside it in the same term, such as a lab paired with its lecture.
Often heard: If a course lists a prerequisite, there is no way around it.
Actually: Prerequisites can often be waived. Transfer credit, placement scores or department approval can override the requirement, though a waiver is granted at the department’s discretion and usually needs supporting evidence.
Going deeper
