Definition from Wiktionary, the free dictionary
- (uncountable) The state or fact of being turbulent or agitated; tempestuousness, disturbance.
- (uncountable) Disturbance in a gas or fluid, characterized by evidence of internal motion or unrest.
- (uncountable) Specifically, a state of agitation or disturbance in the air which is disruptive to an aircraft.
- An instance or type of such state or disturbance.
Related terms 
disturbance in gas, fluid