What is "pleocytosis"

n. A condition where an unusually high quantity of white blood cells (normally lymphocytes) are present in the cerebrospinal fluid

Pleocytosis is an increased cell count {Gk. pleion more}, particularly an increase in white blood cell (WBC) count, in a bodily fluid, such as cerebrospinal fluid (CSF). It is often defined specifically as an increased WBC count in CSF.

Increased white blood cell count in the blood is called leukocytosis.