Heterofullerene is a relatively new term used in the field of nanotechnology to describe a type of fullerenes with non-carbon atoms in the cage-like structure. However, there are several synonyms for heterofullerene, including non-carbon fullerenes, metallofullerenes, and non-shackled fullerenes. Metallofullerenes are a specific type of heterofullerene where the cage-like structure includes one or more metal atoms, whereas non-shackled fullerenes refer to any fullerene that is not pure carbon. Heterofullerenes have been used in a variety of applications, including medicine, solar cells, and electronics. As research in the field of nanotechnology continues, more synonyms may emerge for these fascinating molecules.