The American Heritage® Dictionary of the English Language, 4th Edition
n. A complex polymer, the chief noncarbohydrate constituent of wood, that binds to cellulose fibers and hardens and strengthens the cell walls of plants.
n. A complex non-carbohydrate aromatic polymer present in all wood.
the GNU version of the Collaborative International Dictionary of English
n. A substance characterizing wood cells and differing from cellulose in its conduct with certain chemical reagents.
The Century Dictionary and Cyclopedia
n. An organic substance which forms the characteristic part of wood-cells, bast-cells, and all woody fibers, making the greater part of the weight of most dry wood.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a complex polymer; the chief constituent of wood other than carbohydrates; binds to cellulose fibers to harden and strengthen cell walls of plants
Word Usage
"Brown midrib corn (BMR) is lower in lignin content (about half of normal corn silage), and 6 to 8 percentage units higher in total plant digestibility."