cor·ru·ga·tion \ˌ ̷ ̷ ̷ ̷ˈgāshən\noun (-s) Etymology: Medieval Latin corrugation-, corrugatio, from Latin corrugatus + -ion-, -io -ion 1.: the act of corrugating or state of being corrugated 2.: a ridge or groove of a corrugated surface < gravel roads with corrugations and potholes > 3.: a small furrow used for the distribution of irrigation water