Definition of superheavy:
(adj) :
Much heavier than usual.
(adj) :
(nuclear physics) Describing a transuranic element with an extremely high atomic number; typically taken to mean beyond lawrencium (element 103, the last actinide).
(n) :
(nuclear physics) A superheavy element.
(n) :
(military, informal) A superheavy tank or artillery piece.
(adj) :
(linguistics, of a syllable) stressed more than is usual
(n) :
A superheavy thing.