parenchyma

noun

(Gr. para: near; en; in; khymos: sap, juice) A tissue of higher plants that consists of thin-walled living photosynthetic or storage cells, relatively undifferentiated, frequently with air spaces between them, which may vary in structure and function, capable of division even when mature and that makes up much of the substance of leaves and roots, the pulp of fruits, and parts of stems and supporting structures; these cells may manufacture or store food, and can often divide or differentiate into other kinds of cells. The cortex and pith are composed of parenchyma cells.