having an affinity for eosin dye.

Readily stained with eaosin, red-orange stain.

Eosinophilic is a technical term used by histologists. The context in which this word is used is in describing the microscopic appearance of cells and tissues, as seen down the microscope, after a histological section has been stained with the dye eosin. Eosinophilic, means "loves eosin", which Eosin is an acidic dye, thus the structure being stained is basic.

of or relating to eosinophil