carbon nanotube(n = noun.substance) nanotube - a fullerene molecule having a cylindrical or toroidal shape;
is a kind of fullerene

activated carbon, carbon, carbon 14, carbon arc, carbon arc lamp, carbon atom, carbon black, carbon copy, carbon cycle, carbon dating, carbon dichloride, carbon dioxide, carbon dioxide acidosis, carbon disulfide, carbon monoxide, carbon monoxide gas, carbon monoxide poisoning, carbon paper, carbon process, carbon steel, carbon tet, carbon tetrachloride, carbon tetrahalide, carbon transmitter, nanotube