| Word | Definitions | Synonyms |
|---|---|---|
| melanin | (noun) insoluble pigments that account for the color of e.g. skin and scales and feathers | - |
| phycocyanin | (noun) blue pigment in algae | - |
| pyocyanin | (noun) a toxic blue crystalline antibiotic found in green pus | - |
| safranin | (noun) any of a class of chiefly red organic dyes | Synonyms: saffranine, safranine |