The term 'Call from the Crow's Nest' is a phrase used to describe a lookout on a ship who would call out to alert the crew of any potential danger. The four letter solution to this crossword clue is 'AHOY'. AHOY is an interjection used to call out to someone, usually to attract attention or to express surprise. It is commonly used in maritime contexts and is derived from the Middle Dutch word 'hoi'.