pipe course noun an easy course in college US,1927 From the older, largely forgotten sense of “pipe” as “easy to accomplish”.
“ You are all freshmen,” continued Mr. Fitzhugh, “and you may not be familiar with the term ‘pipe course.’ A pipe course is a course where students can get passing grades without doing much work. This is not a pipe course.” — Max Shulman, TheManyLovesofDobieGillis, p. 96, 1951