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.
Lignins are one of the main classes of structural materials in the support tissues of vascular plants and some algae. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically lignins are cross-linked phenol polymers.