Dissipate/ˈdɪsɪpeɪt/ Definition 1 of 4Pro Tip 1/2Crowd Dispersion Used when people or things spread out and the group breaks up. The fans dissipated after the concert ended. Pro Tip 2/2Fading Quickly Emphasizes the rapid disappearance or vanishing of something, like smoke or fog. The morning fog dissipated by eight o'clock.