'azulene' originates from Spanish, specifically the word 'azul' meaning 'blue', combined with the chemical suffix '-ene' used to denote unsaturated hydrocarbons.

'azulene' was coined in the 19th century after the blue hydrocarbon was isolated from natural sources (e.g., chamomile, guaiac wood); the name fused Spanish 'azul' and the suffix '-ene' (as in other hydrocarbon names like 'benzene'), and entered scientific literature as 'azulene'.

Initially it referred specifically to the naturally occurring blue hydrocarbon; over time the term broadened to include its synthetic derivatives and the azulene structural motif in organic chemistry.