- pyrogen (n.)
- 1858, as a proposed word for "electricity," from pyro- + -gen. Meaning "fever-producer" is from 1896. Related: Pyrogenic; pyrogenetic. Greek pyrogenes meant "born in fire, wrought by fire."
- pyrotoxin
- " Medicine . A pyrogen; specifically a pyrogenic bacterial toxin. Now rare", Late 19th cent.; earliest use found in The Lancet. From pyro- + toxin.