Webster’s Revised Unabridged Dictionary · 1913
Lignin
Lig′nin (lĭg′nĭn), n. [L. lignum wood: cf. F. lignine.] (Bot.) A substance characterizing wood cells and differing from cellulose in its conduct with certain chemical reagents.
☞ Recent authors have distinguished four forms of this substance, naming them lignose, lignin, lignone, and lignireose.