Prefix meaning pus. Pyocephalus is pus in the brain.

(prefix) pus. e.g. pyometra - an accumulation of pus within the uterus. e.g. pyogranuloma - an infiltration of polymorphonuclear cells into an area of chronic inflammation characterized by mononuclear cells, macrophages, lymphocytes and even plasma cells.

PYO refers to pick-your-own farms, a commercial agritourism / agri-entertainment strategy that has been around for decades, but has grown dramatically in the 1990s.

Persistent Young Offender