1 a: a moving ridge or swell on the surface of a liquid (as of the sea) b: open water 2 a: a shape or outline having successive curves b: a waviness of the hair c: an undulating line or streak or a pattern formed by such lines 3: something that swells and dies away: as a: a surge of sensation or emotion <a wave of anger swept over her>b: a movement sweeping large numbers in a common direction <waves of protest>c: a peak or climax of activity <a wave of buying> 4: a sweep of hand or arm or of some object held in the hand used as a signal or greeting 5: a rolling or undulatory movement or one of a series of such movements passing along a surface or through the air 6: a movement like that of an ocean wave: as a: a surging movement of a group <a big new wave of women politicians>b: one of a succession of influxes of people migrating into a region c (1): a moving group of animals of one kind (2): a sudden rapid increase in a population d: a line of attacking or advancing troops or airplanes e: a display of people in a large crowd (as at a sports event) successively rising, lifting their arms overhead, and quickly sitting so as to form a swell moving through the crowd 7 a: a disturbance or variation that transfers energy progressively from point to point in a medium and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential, or temperature b: one complete cycle of such a disturbance 8: a marked change in temperature : a period of hot or cold weather 9: an undulating or jagged line constituting a graphic representation of an action