Meaning

noun any place of pain and turmoil

noun a very intense and uncontrolled fire

noun (Christianity) the abode of Satan and the forces of evil; where sinners suffer eternal punishment; - John Milton; ; -Dr. Johnson

originFrom Italian inferno (“hell”), from Latin infernus (“of the lower regions”), inferna (“the lower regions”); see infernal. The meaning "big fire" came as a figurative use from the traditional idea of hellfire.

Etymology from Wiktionary, CC BY-SA 3.0