Merriam-Webster's Collegiate® Dictionary, 11th Edition
POUR
I. verb
Etymology: Middle English
Date: 14th century
transitive verb
1. to cause to flow in a stream, to dispense from a container , to supply or produce freely or copiously , to give full expression to ; vent , intransitive verb to move with a continuous flow, to rain hard, to move or come continuously ; stream , to score easily or freely (as in basketball), pourable adjective pourer noun pouringly adverb
II. noun
Date: 1790
the action of pouring ; stream ,
2. an instance of pouring or an amount poured, a heavy fall of rain ; downpour