The term 'third' can be used to describe a variety of things. The first crossword solution is 'tertiary, ' which means third in order or rank. This is often used to describe educational institutions, such as tertiary education, which refers to post-secondary education. The second solution is 'RAIL, ' which is a type of transportation that runs on tracks and is often used for long-distance travel. The third solution is 'Reich, ' which is a German word meaning empire or realm. It is most commonly associated with the Nazi regime in Germany during World War II.