The term 'bound to happen' can be described by several crossword solutions, including DESTINY (7 letters), FATE (4 letters), FATED (5 letters), SURE (4 letters), and LEAP (4 letters). DESTINY is a predetermined course of events that are considered to be inevitable, while FATE is an event that is predetermined by a supernatural power. FATED is an adjective used to describe something that is destined to happen, and SURE is an adjective used to describe something that is certain to happen. Finally, LEAP is a verb meaning to move suddenly and quickly in a particular direction. All of these words can be used to describe something that is bound to happen, as they all imply that the event is predetermined and unavoidable.