The term 'wing movement' can be summarized by the crossword solution 'FLAP, ' which is a four-letter word. Flapping is a type of movement used by birds and other flying animals to generate lift and propel themselves through the air. This motion is created by the up-and-down movement of the wings, which causes air to flow over and under them. This creates an area of low pressure above the wings and an area of high pressure below them, resulting in lift.