/pəˈrɛŋkɪmə/
Noun
1. The essential and distinctive tissue of an organ or an abnormal growth as distinguished from its supportive framework. (merriam-webster.com)
2. Animal tissue that constitutes the essential part of an organ as contrasted with e.g. connective tissue and blood vessels. (wordnetweb.princeton.edu)
3. The primary tissue of higher plants composed of thin-walled cells that remain capable of cell division even when mature; constitutes the greater part of leaves, roots, the pulp of fruits, and the pith of stems. (wordnetweb.princeton.edu)
4. In plants, tissue typically composed of living cells that are thin-walled, unspecialized in structure, and therefore adaptable, with differentiation, to various functions. Parenchyma may be compact or have extensive spaces between the cells. It is often called ground, or fundamental, tissue and makes up the mesophyll (internal layers) of leaves and the cortex (outer layers) and pith (innermost layers) of stems and roots; it also forms the soft tissues of fruits. (global.britannica.com)
Word origin: From Greek parenkhyma “something poured in beside,” from para– “beside” + enkhyma “infusion,” from en– “in” + khein “to pour”