A course completed primarily by solitary study. Differing from a correspondance course in that the material may be less regimented and occasional1 visits with a supervisor are involved.
Courses are often offered as a reading course if there are not enough students to warrant lectures and tutorials or the professor doesn't have time. In addition, many upper-year university courses are offered biyearly but exceptions are sometimes made through the guise of reading courses.
In the senior year2 of an undergraduate degree a student has the option of pursuing one Reading Course per subject. Less specific than an undergraduate thesis, this designation tends to be applied to anything academic that doesn't fit into another special course's domain. In some departments this domain will be very small whereas in others it is the only option for self-directed study. Rather than a thesis or research practicum, a Reading Course allows for more flexibility in methods of assessment.
For reading courses at Trent University I had to fill out a form five months in advance that included:
I am using a course of this type to do research into a topic (Bertrand Russell's philosophy of language and logic, in case you were wondering) that is a small portion of regular courses. The outline for the course is based on similar senior courses. I may also use this designation to do a research project in Computer Science.
1: Trent University requires a minimum of 6 meetings per term.
2: They are possible in the junior year but quite rare.