The crossword solutions for the term 'Allow to Happen' are 'ENABLE' (6 letters) and 'LET' (3 letters). Both words mean to give permission or make something possible. ENABLE implies that someone is given the power or ability to do something, while LET implies that someone is allowed to do something. Both words can be used in a variety of contexts, such as allowing someone to do something, allowing something to happen, or enabling someone to do something.