naphthalene

From naphtha +‎ -ene

naphthalene (usually uncountable, plural naphthalenes)

1. A white crystalline hydrocarbon manufactured from coal tar; used in mothballs.
2. (organic chemistry) An aromatic bicyclic hydrocarbon, C₁₀H₈; an acene containing two fused benzene rings.

(2-ring aromatic hydrocarbon):

• acene

(2-ring aromatic hydrocarbon):

• benzene (1-ring acene)
• anthracene (3-ring acene)