Noun
(kayaking) The act of turning one's kayak from an upright position, laterally 360 degrees (going underwater and coming back up) while still moving forward.
Synonym: kayak roll
Did you see that instructor do an Eskimo roll in this freezing water?
(surfing) The act of rolling under one's surfboard to dive through a wave, when heading out from shore.
Source: en.wiktionary.org