foreign-object damage (FOD)
Damage caused to an engine by a foreign object (i.e., objects not belonging to the engine). The damage is caused by items like rags, pieces of paper, line, articles of clothing, nuts, bolts, stones, or tools misplaced or caught by air currents normally found around aircraft operations (jet blast, rotor or prop wash, engine intake). This damage can be in the form of nicks, cuts, tears, and even fractures of components, especially rotor and turbine blades.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved