Definition of fullerene:
(n) :
(inorganic chemistry) Any of a class of allotropes of carbon having hollow molecules whose atoms lie at the vertices of a polyhedron having 12 pentagonal and 2 or more hexagonal faces.
(n) :
(organic chemistry) Any closed-cage compound having twenty or more carbon atoms consisting entirely of 3-coordinate carbon atoms.
(n) :
(chemistry, by extension) The class of carbon allotropes consisting of tubular carbon molecules (carbon nanotubes) and spheroidal carbon molecules (traditional fullerenes).