1. a complex organic polymer found in the cell walls of plants that provides structural support and rigidity to wood and other plant tissues
Usage: technical/scientific term; uncountable noun

Examples

• Lignin makes up about 25% of wood and gives trees their strength.
• The breakdown of lignin is essential in the paper-making process.
• Plants use lignin to reinforce their cell walls and resist bending.
• Lignin is one of the most abundant organic polymers on Earth.
• Scientists are studying how to extract lignin from wood waste for industrial uses.