The archaic
Proto-Indo-European language (ca. 4500鈥4000 BC) had a two-gender system which originally divided words between animate and inanimate, a system used to distinguish a common term from its deified synonym. Therefore, fire as an animate entity and active force was known as *h鈧乶胎g史nis, while the inanimate entity and natural substance was named *p茅h鈧倁r (cf.
Greek: 蟺蠀蟻, pyr; English: fire).[1][2]
In some traditions, as the sacral name of the dangerous fire may have become a
word taboo,[3] the stem *h鈧乶胎g史nis served as an ordinary term for fire, as in the Latin ignis.[1]
Mallory, James P.; Adams, Douglas Q. (2006). The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World. Oxford, UK: Oxford University Press.
ISBN978-0-19-929668-2.