mindmap root((敲打)) tap implies making a light blow usually repeated: ~ on the window to attract a friend's attention. knock implies a firmer blow, sometimes amounting to a pounding or hammering, and a correspondingly louder sound: the messenger ~ed loudly to awaken us. rap suggests a smart vigorous striking on a hard surface that produces a sharp quick sound or series of sounds: the chairman ~ped for order. trump implies a solid pounding or beating that produces a dull booming sound: heard the ~ing and banging of carpenters working on the floor below. thud places more emphasis on the sound and often implies the result of something falling or striking rather than of something being struck: heard the severed tree limbs ~ as they fell.