1. a chemical group consisting of one carbon atom bonded to two hydrogen atoms (CH₂)
Usage: chemistry
2. a blue dye used as a biological stain and antiseptic
Usage: chemistry; medicine

Examples

• The methylene group is a common structural unit in organic compounds.
• Methylene blue is used to stain cell nuclei in microscopy.
• The polymer chain contains repeating methylene units.
• Doctors sometimes use methylene blue as an antiseptic solution.
• The methylene bridge connects two aromatic rings in the molecule.
• Laboratory technicians prepared a methylene blue solution for the experiment.