The word "轰炸" is formed by combining the characters "轰" and "炸", where "轰" conveys the concept of a loud, explosive sound or action, such as thunder or bombardment, and "炸" directly means to explode or blast; together, they create a compound meaning that refers to the act of bombing or shelling, with "轰" emphasizing the overwhelming force or noise and "炸" specifying the explosive nature.