Meaning

noun animal tissue that constitutes the essential part of an organ as contrasted with e.g. connective tissue and blood vessels

noun 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

originFrom Ancient Greek παρέγχῠμα (parénkhŭma, “anything poured in beside”), from πᾰρᾰ- (pără-, “beside”) + ἔγχῠμα (énkhŭma, “instillation, content of a vessel”), given by the Greek anatomist Erasistratus to the peculiar substance of the lungs, liver, kidneys, and spleen, as if formed separately by the veins that run into them. By surface analysis, para- + -enchyma.

Etymology from Wiktionary, CC BY-SA 3.0