The term 'Cause of Collapse' can be summarized by the crossword solution 'STRAIN'. STRAIN is a term used to describe the amount of stress or pressure that is placed on an object or system. In this context, it can refer to the amount of stress that is placed on a structure or system, which can lead to its collapse if the STRAIN is too great. This can be caused by a variety of factors, such as natural disasters, human error, or structural defects.