'bilirubin' originates from Latin, specifically the words 'bilis' meaning 'bile' and 'ruber' meaning 'red'.

'bilirubin' was derived from the Latin words 'bilis' and 'ruber', and eventually became the modern English word 'bilirubin'.

Initially, it meant 'red bile', but over time it evolved into its current meaning of a yellow compound involved in heme breakdown.