Greek Fire, a combustible of highly inflammable quality, but of uncertain composition, used by the Greeks of the Byzantine Empire against the Saracens; a source of great terror to those who were assailed by it, as it was difficult to extinguish, so difficult that it was said to burn under water.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Greek * Greeley, Horace