<p><strong>Verb</strong></p><ul><li>to rove over (a country, region, etc.); invade; ravage: a time when looting hordes had overrun the province.</li><li>to swarm over in great numbers, as animals, especially vermin; infest: The house had been overrun by rats.</li><li>to spread or grow rapidly over, as plants, especially vines, weeds, etc.: a garden overrun with weeds.</li><li>to attack and defeat decisively, occupying and controlling the enemy's position; overwhelm.</li><li>to spread rapidly throughout, as a new idea or spirit: a rekindling of scholarship that had overrun Europe.</li><li>to run or go beyond, as a certain limit: The new jet overran the landing field.</li><li>to exceed, as a budget or estimate: to overrun one's allotted time.</li><li>to run over; overflow: During the flood season, the river overruns its banks for several miles.</li><li>Printing: to print additional copies of (a book, pamphlet, etc.) in excess of the original or the usual order.</li><li>Nautical: to sail past (an intended stopping or turning point) by accident.</li><li>(of a ship) to complete (a schedule of calls) more rapidly than anticipated.</li><li>to outrun; overtake in running.</li></ul><p><strong>Noun</strong></p><ul><li>an act or instance of overrunning.</li><li>an amount in excess; surplus: an overrun of 10,000 copies of a new book.</li><li>the exceeding of estimated costs in design, development, and production, especially as estimated in a contract: a staggering overrun on the new fighter plane.</li><li>the amount exceeded: an overrun of $500,000 for each fighter plane.</li><li>a run on an item of manufacture beyond the quantity ordered by a customer and often offered at a discount.</li><li>the amount by which the volume of a food, as butter or ice cream, is increased above the original volume by the inclusion of air, water, or another substance: With only a 20 percent overrun, this is an excellent ice cream.</li></ul>