OverRun

Overrun is a term used as both a verb and a noun with several related meanings. As a verb, it means to spread over and occupy an area beyond its capacity or boundaries; to overwhelm or invade by a rapid, often forceful advance; to exceed a limit. As a noun, an overrun can refer to the act of overrunning or to a place or situation that has been overtaken by a force, growth, or influx.

In military usage, an overrun denotes the rapid capture of a position or territory by opposing forces, typically following a breach of defenses, flank maneuver, or sudden assault. An overrun can disrupt command, logistics, and morale, and may indicate a lapse in preparation or resistance.

In project management and engineering, overrun commonly describes costs or schedules that exceed planned amounts. A cost overrun occurs when actual expenditures exceed the budget; a schedule overrun when completion extends beyond the planned deadline. Overruns are evaluated in risk assessments and can prompt scope adjustments and contingency planning.

In ecology and everyday language, overrunning can refer to a species, plant, or population that spreads to dominate a habitat, sometimes constituting an invasive spread. The term can describe spaces crowded by people or activity, such as a venue overrun with attendees. In general use, overruns indicate a failure to limit growth, demand, or resource use within intended bounds.