The term COLLIER ENTRANCE is composed of two words. The first word, 'COLLIER, ' is a noun meaning a coal miner or a ship that carries coal. The second word, 'ENTRANCE, ' is a noun meaning an opening or doorway. Together, the term COLLIER ENTRANCE refers to an ENTRANCE or opening used by coal miners. The crossword solution for this term is ADIT, which is a noun meaning an underground tunnel or passage used for mining. Therefore, the term COLLIER ENTRANCE can be defined as an ENTRANCE or opening used by coal miners, typically in the form of an underground tunnel or passage.