Girasol definition, an opal that reflects light in a bright luminous glow. See more.
Pheophytin or phaeophytin (abbreviated Pheo) is a chemical compound that serves as the first electron carrier intermediate in the electron transfer pathway of Photosystem II (PS II) in plants, and the photosynthetic reaction center (RC P870) found in purple bacteria.
There is no mention of context, but if it's referring to a medical condition, perhaps what is meant is pheo, which is medical slang for pheochromocytoma, a benign tumor of the adrenal gland associated with severe high blood pressure. Wikipedia has an article on it.