nepˈt(y)ünēəm sometimes -pˈchü- noun
( -s )
Etymology: New Latin, from International Scientific Vocabulary Neptune, the planet Neptune (from Latin Neptunus, the god Neptune) + New Latin -ium
: a radioactive metallic element of the actinide series that is similar chemically to uranium, that was discovered as a short-lived isotope by spontaneous emission of an electron from uranium 239 produced in turn by neutron bombardment of uranium 238, and that is obtained as the longest-lived isotope in nuclear reactors as a by-product in the production of plutonium — symbol Np ; see element table