Flatheads

Flatheads refer to several different things in different contexts.

In hardware, flathead describes a screw with a flat, straight slot across its head, designed to sit flush in a countersunk hole. The term is commonly used for screws with a slotted head, sometimes called slotted screws.

In ichthyology, flathead most often denotes the flathead catfish (Pylodictis olivaris), a large freshwater fish native to North America. It has a broad, flattened head and a slender body, and is typically found in rivers and lakes. It is a bottom-dweller and preys on smaller fish.

In automotive history, a flathead refers to the flathead V8 engine design, notably used by Ford beginning in 1932. The name comes from the engine block and cylinder head sharing a flat surface. It was simple and inexpensive to manufacture but less efficient than modern overhead-valve designs, leading to its replacement by newer configurations.

In ethnography and geography, Flathead has historically referred to the Salish-speaking people of western Montana, often called the Flatheads by neighboring groups and early settlers. Today the term is considered outdated by many, with preference given to Salish or to the name of the relevant tribe (Confederated Salish and Kootenai Tribes). Several places in Montana—Flathead Lake, Flathead National Forest—bear the name due to historic associations.