I have, on occasion, heard "Top Hats" (see link) referred to as a "High Hat", although I suppose it's just a confusion from those who work with bands a lot. They are similar in shape to a recessed lighting fixture and, when attached to the appropriate luminaire. http://www.citytheatrical.com/la_1_info.htm
Ok, I just had to come up with a post that included both words.
