flu̇(ə)ˈresēə̇n, flōˈ-, flȯˈ- noun
( -s )
Etymology: fluoresce + -in
: a yellow granular or red crystalline phthalein dye C 20 H 12 O 5 giving a brilliant yellow-green fluorescence in alkaline solution and having a number of applications based chiefly on its visibility at high dilution or its ready conversion to eosin and related dyes — see dye table I (under Acid Yellow 73 )