At schools with a block schedule, Third Friday is only present if Friday is a day off. It is the actual Friday of the week, because Wednesday
is the last day you have one set of classes then Thursday
is the last day you have the other set of classes, and then there is the real Friday
If Thursday and Friday are both days off there are still only three possible Fridays (because Thursday is more like a first Saturday); although, First and Second Friday are moved back one day... Third Friday can also be called "normal Friday" or just "Friday."