Define vertebrate: any of a subphylum (Vertebrata) of chordates that comprises animals (such as mammals, birds, reptiles, â¦ â vertebrate in a sentence any of a subphylum (Vertebrata) of chordates that comprises animals (such as mammals, birds, reptiles, amphibians, and fishes) typically having aâ¦ See the full definition
Definition of LIGNITE. : a usually brownish black coal intermediate between peat and bituminous coal; especially: one in which the texture of the original wood is distinct âcalled also brown coal.
The chemical composition of lignin has not been conclusively established. The lignin molecule consists of the products of polymerization of aromatic alcohols, and the basic monomer is coniferyl alcohol: Lignin is an amorphous substance, yellowish brown in color; it is insoluble in water and organic solvents. It is stained by basic dyes and yields color reactions characteristic of phenols. The biosynthesis of lignin has not been completely studied.