chym-, chymo-, chymi-

1. Embryonic cell mass including the cells within the embryo (pre-fetal development) that develop into connective tissue, bone, cartilage, blood, and the lymphatic system.
2. The part of the embryonic mesoderm, consisting of loosely packed, unspecialized cells set in a gelatinous ground substance, from which connective tissue, bone, cartilage, and the circulatory and lymphatic systems develop.
3. Etylmology: from Greek meso-, "middle, between" + Greek enchyma, "infusion"; from en-, "in, into" + Greek chymos, "juice"; from cheein, "to pour, to spill".

The term mesenchyme was introduced into embryology by the German embryologists Oskar Hertwig (1849-1922) and his brother Richard (1850-1937) in 1881.

1. The key elements of an organ essential to its functioning, as distinct from the capsule that encompasses it and other supporting structures.

The parenchyma is therefore opposed to the connective tissue framework, or stroma, of an organ. The parenchyma of the testis consists of what are called the seminiferous tubules.

2. Etymology: from the Greek word parenchyma, "that which is poured in". It reflects the error of an ancient idea that the inner substance of solid organs like the liver, spleen, and kidneys was formed by blood that was "poured into it".