What is the meaning of Hammerhead?

The portion of a hammer containing the metal striking face (also including the claw or peen if so equipped).

Any organism with head shaped like that of a hammer:

Any shark of the family Sphyrnidae, which only includes the genera Sphyrna and Zygaena, with eyes set on projections from the sides of the head.
A hogsucker, a fresh-water fish of species Hypentelium nigricans, in the sucker family Catostomidae.
A hammer-headed fruit bat, a fruit bat of species Hypsignathus monstrosus, with a large blunt nozzle.
A hammerkop, a bird of species Scopus umbretta.

Any shark of the family Sphyrnidae, which only includes the genera Sphyrna and Zygaena, with eyes set on projections from the sides of the head.

A hogsucker, a fresh-water fish of species Hypentelium nigricans, in the sucker family Catostomidae.

A stupid person, a dunce.

A turn-around; a parking area constructed in a subdivision for initial access and construction.

Source: wiktionary.org

See also