Sentence:  I turned the key, the lock gave a <WSD>click</WSD> and the door opened;  a <WSD>click</WSD> of one's fingers 
Meaning of the word marked with <WSD> tags:  A brief, sharp, not particularly loud, relatively high-pitched sound produced by the impact of something small and hard against something hard, such as by the operation of a switch, a lock or a latch, or a finger pressed against the thumb and then released to strike the hand.