The term 'sets off' can be defined as initiating an action or reaction. This can be seen in the crossword solutions given, such as 'EMBARKS' (7 letters), which means to start a journey, 'trips' (5 letters), which means to set off an event, 'TRIGGERS' (8 letters), which means to set off an action or reaction, 'detonates' (9 letters), which means to set off an explosive device, 'SPARKS' (6 letters), which means to set off a reaction, 'begins' (6 letters), which means to start something, 'IGNITES' (7 letters), which means to set off a fire, 'starts' (6 letters), which means to initiate an action, and 'enrages' (7 letters), which means to set off an angry reaction. All of these words are related to the term 'sets off' in that they all refer to initiating an action or reaction.