/es"pee euh nahzh', -nij, es'pee euh nahzh"/ , n.
1. the act or practice of spying.
2. the use of spies by a government to discover the military and political secrets of other nations.
3. the use of spies by a corporation or the like to acquire the plans, technical knowledge, etc., of a competitor: industrial espionage.
[ 1785-95; espionnage, MF espionage, equiv. to espionn ( er ) to spy (deriv. of espion spy spione spähen to look out) + -age -AGE ]