Originally posted on November 21, 2012.
Only in economics are floors above ceilings! It might be better to say "a minimum allowed price above the market price" and "a maximum allowed price below the market price," although that is a bit of a mouthful. I find that the floors and ceilings language does work, however, if the instructor explicitly points out the oddity of floors above ceilings! In that case, students find the distinction memorable.