The term 'BIG UMBRELLA' can be summarized by the crossword solution GAMP, which stands for 'Global Alliance for Mass Participation'. This is an international organization that was founded in 2014 to promote and support mass participation in sports and physical activity. It works to create a global network of organizations, governments, and individuals who are committed to increasing access to sport and physical activity. The organization also works to ensure that everyone has the opportunity to participate in sport and physical activity regardless of their background or ability.