1. being perturbed: disturbance and trouble, a disturbed and troubled state, or the act of disturbing and troubling somebody or something
2. cause of trouble: something that causes disruption, trouble, or disorder
3. physics disturbance caused by secondary influence: a slight disturbance of a system by a secondary influence within it
4. astronomy deviation in orbit caused by gravity: a deviation in an astronomical object's orbit or path caused by the gravitational attraction of another astronomical object
