boat·er \ˈbōd.ə(r), -ōtə-\noun (-s) 1.: one that rows a boat for a livelihood or as a pastime < boaters on the river > 2.[so called from its having been worn typically by boaters]chiefly Britain: a man's stiff straw hat with a flat crown, ribbon band, and straight brim 3.: a woman's hat adapted from the man's boater