Random courses

(Masonry) courses of stone of unequal thickness.

See also: Random

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
This means they have found themselves signing up to random courses irrelevant to their area of practice.
"When the time is taken to look at transferrable courses, with a specific goal in mind, rather than taking random courses, the savings could add up considerably."