What is the difference between dropping a class and withdrawing from a class?

The first seven days of a semester (or the first three days of the summer session) is the add/drop period, in which you can adjust your courses to best fit your interests and academic goals. During open registration for the subsequent semester and during the open reregistration period immediately prior to the semester's beginning, you may add and drop classes in APR2. After this, you must use an add/drop form, which requires the approval of any instructor whose class you wish to add. For any class you are dropping, you must fill out the course and section information and instructor name, and you must inform the instructor immediately. Though your advisor's approval is not required, it is important to be in close contact with your advisor about all changes to your schedule.

If you fail to submit the add/drop form on time, you may petition after the deadline to add/drop a course that you have/have not been attending, so that your enrollment status properly reflects the reality of the courses you are in fact taking. If your petition is approved, you will be assessed a late schedule change fee.

Once the add/drop period has ended, you are expected to stay in the courses for which you have enrolled for the entire semester. However, if you find yourself in serious academic distress in a course after this deadline, you may withdraw from a course. Unlike in the case of add/drop, a course you have withdrawn from remains listed on your transcript, but with the notation "W" denoting the withdrawal. It does not contribute to your GPA, nor does it contribute credit toward graduation. You may withdraw from a  maximum of two courses during your time at St. Lawrence. Note that students with financial aid, students in the US on a student visa, and NCAA student-athletes must consult with the relevant office and their academic advisor before withdrawing from a course, if the withdrawal will reduce their active courseload below 3.5 units, as there may be significant eligibility consequences.

Note that you may not drop a course you have been attending after the add/drop period is over. You are enrolled in the course at that point, so you must withdraw if you wish to get out of the course.