dy·nam·ics / dīˈnamiks/ • pl. n. 1. [treated as sing.] the branch of mechanics concerned with the motion of bodies under the action of forces. Compare with statics. ∎ the branch of any science in which forces or changes are considered: chemical dynamics.2. the forces or properties that stimulate growth, development, or change within a system or process: the dynamics of changing social relations.3. Mus. the varying levels of volume of sound in different parts of a musical performance.DERIVATIVES: dy·nam·i·cist / -ˈnaməsist/ n. (in sense 1).