The word "快闪" is formed by combining the character "快", meaning "fast" or "quick", with "闪", meaning "flash" or "dart", to create a compound that literally translates to "fast flash". This term was coined to describe organized public events where participants gather abruptly, perform a brief, unexpected action, and then quickly disperse, directly deriving from the English concept of a "flash mob". The characters are used semantically, with "快" emphasizing the speed of assembly and "闪" highlighting the fleeting, instantaneous nature of the event.