Naval Post is a term used to describe a military post or station that is located near a body of water, such as an ocean, lake, or river. The term is derived from the Latin word for 'SHIP' and is often used to refer to a naval base or port. The term MAST, which is a four-letter solution to the crossword puzzle, is an acronym for Maritime Air Surveillance and Targeting. This term refers to the use of radar and other surveillance systems to detect and track ships and other vessels in the area.