perturˈbant noun

Anything that perturbs

Perturbing

perturbāˈtion noun

1. The act of perturbing or state of being perturbed
2. Disquiet of mind
3. Irregularity
4. The disturbance produced in the simple elliptic motion of one heavenly body around another by the action of a third body, or by the non-sphericity of the principal body (astronomy)
5. Disturbance in a system caused by an outside influence
6. A perturbing agent

perturbāˈtional adjective

perturˈbative adjective

perˈturbātor noun

perturˈbatory adjective and noun

perturbedˈ adjective

perturˈbedly adverb

perturˈber noun

perturbation theory noun (physics)

A mathematical method of determining the effect of small local changes on the behaviour of a system