ˈfȯilgən- noun
Usage: usually capitalized F
Etymology: after Robert Feulgen b 1884 German physiologist
: the development of a purplish color in a microscopic preparation hydrolyzed and stained with a modified Schiff reagent that is considered to indicate the presence of chromatin and used to identify chromatinic structures in cells or as an aid in distinguishing nuclei in various microorganisms