etioporphyrin
noun
etio·por·phy·rin
variants:
or chiefly British aetioporphyrin \ -ˈpȯr-fə-rən 
\
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Medical Definition of etioporphyrin
: any of four isomeric porphyrins C32H38N4
especially
: a violet crystalline pigment occurring in nature (as in petroleum and coal) and formed by degradation of chlorophyll and of heme