triton

noun

the nucleus of the tritium atom containing one proton and two neutrons, used as a projectile in nuclear reactions

noun

Gr. Myth. a sea god, son of Poseidon and Amphitrite, represented as having the head and upper body of a man and the tail of a fish and as carrying a conch-shell trumpet
Gr. Myth. one of many attendants of the sea gods
the largest of Neptune's eight satellites
1. any of a family (Cymatiidae) of large sea snails with a long, spiral shell, often brightly colored
2. the shell

See triton in American Heritage Dictionary 4