Early 19th century; earliest use found in Robert Heron (1764–1807), journalist and author. From pyrophorus + -ous; compare -phorous. Cf earlier pyrophoric.
Definition of pyrophorous in US English:
pyrophorous
adjectivepʌɪˈrɒf(ə)rəs
rare
Pyrophoric 2.
Origin
Early 19th century; earliest use found in Robert Heron (1764–1807), journalist and author. From pyrophorus + -ous; compare -phorous. Cf earlier pyrophoric.