noun A (sudden) flood or inundation of water; specifically, a flood in or overflow of a river or other watercourse due to heavy rain or melting snow; flooding, inundation.
noun A sudden heavy downpour of rain.
noun A sudden increase or rush of something; a flood, an outburst, an outpouring.
verb To (suddenly) flood or inundate (a river or other watercourse) with water.