1. a clear liquid solution of formaldehyde in water, used as a preservative and disinfectant
Usage: chemistry; medical

Examples

• The biology specimens were preserved in formalin for the lab experiment.
• The pathologist placed the tissue sample in formalin before examination.
• Formalin is commonly used in medical laboratories to preserve organs.
• The museum used formalin to preserve the animal specimens in their collection.
• Students observed the formalin-preserved frog during their dissection class.
• The hospital’s pathology department stores tissue samples in formalin solution.