"woody tissue in higher plants," 1875, from German Xylem, coined from Greek xylon "wood," of unknown origin.
A tissue in vascular plants that carries water and dissolved minerals from the roots and provides support for softer tissues. Xylem consists of several different types of cells: fibers for support, parenchyma for storage, and tracheary elements for the transport of water. The tracheary elements are arranged as long tubes through which columns of water are raised. In a tree trunk, the innermost part of the wood is dead but structurally strong xylem, while the outer part consists of living xylem, and beyond it, layers of cambium and phloem. See more at cambium, capillary action. Compare phloem.