1. A situation in which an element thrives in a pungent medium or in a substance that is sour: Acidophily is an organism's ability to grow in an acidic habitat (pH below 5.5) and therefore having a high density of protons.
2. A condition in which a substance has an affinity for acid dyes: Acidophily can denote a cell or tissue element that stains with an acid dye, such as eosin which is a red fluorescent dye that is used in cosmetics or as a biological stain for studying cell structures.
3. A circumstance in which microorganisms or plants flourish in acetous habitats that are very sour: Acidophily is a situation of vegetation growing successfully in acidic environments.