The Collaborative International Dictionary of English v.0.48:

Pinenchyma \Pi*nen"chy*ma\, n. [NL., fr. Gr. pi`nax a tablet +
   -enchyma, as in parenchyma.] (Bot.)
   Tabular parenchyma, a form of cellular tissue in which the
   cells are broad and flat, as in some kinds of epidermis.
   [1913 Webster]