noun, plural: tracheids
(botany) A tubular cell in the xylem of vascular plants that functions primarily in the conduction of water and mineral salts collected by the roots to other parts of the plant (e.g. stem, leaves, fruits). It also provides structural support to plants.
Tracheids are one of the two types of tracheary elements of vascular plants. (The other being the vessel elements). A tracheid cell loses its protoplast at maturity. Its secondary cell wall is lignified. It interconnects with neighboring tracheid cells through pits where the cell wall is modified into a thin membrane so that water can move across from one tracheid cell to another.