The term 'burst suddenly' can be described by four different words, all of which have a different number of letters. The first word is 'IRRUPT' (6 letters), which means to enter or appear suddenly and often violently. The second word is 'POP' (3 letters), which means to make a short, sharp sound. The third word is 'GUST' (4 letters), which means a sudden strong rush of wind. The fourth word is 'SALVO' (5 letters), which means a simultaneous discharge of guns or missiles. All of these words describe the same action of bursting suddenly.