■ noun
1》 an edible tropical marine fish that has a pointed flattened head with the eyes on the top. [Family Platycephalidae: several species.]
2》 ( Flathead ) a member of certain North American Indian peoples who practised or were believed to practise head-flattening, including the Chinook.
3》 [as modifier ] US denoting an engine having the valves and spark plugs in the cylinder block rather than the cylinder head.
4》 [as modifier ] N. Amer. (of a screw) countersunk.