What does irrigate mean?

Irrigation in its most common definition is the watering system used to grow crops.

Irrigation is defined as the process of artificially supplying water to the soil for raising crops. It is the engineering of controlling and harnessing the various natural source of water by the construction of dams and reservoirs.
Irrigation is an artificial application of water to the soil. It is usually used to assist the growing of crops in dry areas and during periods of inadequate rainfall.