doubleheaded

Doubleheaded is an adjective used to describe something that has two heads. The term is applied in biology, heraldry, and cultural contexts to indicate dual cranial structures or symbolic representation of dual realms or ideas.

In biology, the term often refers to a condition known as dicephaly, a form of conjoined twinning where two heads share a single body or are connected by part of the torso or necks. Dicephalic individuals or animals arise from incomplete embryo splitting during development. The anatomical arrangement and extent of organ sharing influence functionality and viability, and outcomes vary widely across cases and species.

In heraldry, the double-headed eagle is a prominent symbol used in various empires and states to denote sovereignty and power across two domains or directions. Its origins trace to the Byzantine Empire and it was adopted by the Holy Roman Empire, later appearing in the insignia of Russia, Albania, and other nations. The two heads are commonly depicted facing opposite directions, interpreted as a watchful gaze toward both east and west or as a representation of unity between different realms.

In culture and fiction, doubleheaded figures appear as monsters, symbols of duality, or as devices to explore themes such as coexistence of opposing forces or dual consciousness. They recur in folklore, literature, and modern media, often serving as allegorical elements rather than literal biological descriptions.

Overall, doubleheaded denotes dual heads in real or symbolic form and is used across disciplines to convey complexity, power, or duality.