noun, plural os·preys.
- Also called fish hawk. a large hawk, Pandion haliaetus, that feeds on fish.
- a plume for trimming hats.
- a large broad-winged fish-eating diurnal bird of prey, Pandion haliaetus, with a dark back and whitish head and underparts: family PandioridaeOften called (US and Canadian): fish hawk
- any of the feathers of various other birds, used esp as trimming for hats
n.fishing hawk, mid-15c., from Anglo-French ospriet, from Medieval Latin avis prede “bird of prey,” from Latin avis praedæ, a generic term apparently confused with this specific bird in Old French on its similarity to ossifrage.