1. a yellowish-red crystalline compound that produces a bright green fluorescence in alkaline solution, used as a dye and tracer
Usage: chemistry; medical

Examples

• The doctor injected fluorescein into the patient’s bloodstream to examine the retinal blood vessels.
• Fluorescein dye was added to the water to trace the underground flow patterns.
• The bright green glow indicated the presence of fluorescein in the solution.
• Researchers used fluorescein to mark the cells for microscopic observation.
• The ophthalmologist used fluorescein drops to detect corneal abrasions.
• Environmental scientists released fluorescein into the river to study water movement.