Definitions of gamma:

noun: the 3rd letter of the Greek alphabet
noun: a unit of magnetic field strength equal to one-hundred-thousandth of an oersted
noun: Portuguese navigator who led an expedition around the Cape of Good Hope in 1497; he sighted and named Natal on Christmas Day before crossing the Indian Ocean (1469-1524)
name: A surname (very rare: popularity rank in the U.S.: #51747)