Flyboat \Fly"boat`\, n. [Fly + boat: cf. D. vlieboot.] 1. (Naut.) A large Dutch coasting vessel. [1913 Webster] Captain George Weymouth made a voyage of discovery to the northwest with two flyboats. --Purchas. [1913 Webster] 2. A kind of passenger boat formerly used on canals. [1913 Webster]