seaway Syllabification: (sea·way)Pronunciation: /ˈsēˌwā/Translate seaway | into Spanish Definition of seaway noun 1an inland waterway capable of accommodating seagoing ships. (the Seaway)see St. Lawrence Seaway. a natural channel connecting two areas of sea. a route across the sea used by ships. 2 [in singular] a stretch of water in which a sea is running:with the engine mounted amidship, the boat pitches less in a seawayseaway in other Oxford dictionaries Definition of seaway in the British & World English dictionary