skeg Syllabification: (skeg)Pronunciation: /skeg/ (also skag)Definition of skeg noun a tapering or projecting stern section of a vessel’s keel, which protects the propeller and supports the rudder. a fin underneath the rear of a surfboard. Origin: early 17th century: from Old Norse skegg 'beard', perhaps from Dutch schegskeg in other Oxford dictionaries Definition of skeg in the British & World English dictionary