a hostile entrance into or invasion of a place or territory, especially a sudden one; raid: The bandits made brief incursions on the village.
2.
a harmful inroad.
3.
a running in: the incursion of sea water.
Origin: 1400–50;late Middle English < Latinincursiōn- (stem of incursiō) raid, equivalent to incurs(us) (past participle of incurrere to incur) + -iōn--ion; see excursion