'bicephalic' originates from New Latin, specifically the word 'bicephalicus', where 'bi-' meant 'two' and the Greek element 'kephalē' meant 'head'.

'bicephalicus' was formed in scientific/medical Latin from Latin/Greek elements (Latin prefix 'bi-' + Greek 'kephalē'), and entered English as 'bicephalic' via Neo-Latin usage in medical and descriptive contexts.

Initially it meant 'having two heads' in literal anatomical or descriptive senses; over time the term has retained that primary meaning and has also been applied metaphorically to describe dual leadership or dual centers of authority.