bilirubin n 1: an orange-yellow pigment in the bile that forms as a product of hemoglobin; excess amounts in the blood produce the yellow appearance observed in jaundice [syn: {bilirubin}, {hematoidin}, {haematoidin}]
Bilirubin \Bil`i*ru"bin\, n. [L. bilis biel + ruber red.] (Physiol.) A reddish yellow pigment present in human bile, and in that from carnivorous and herbivorous animals; the normal biliary pigment. [1913 Webster]