An inferno is a raging blaze. A fire so large that fighting it is no longer the point.
Journalism uses it for the biggest fires, and a blazing inferno is close to a fixed phrase despite being a repetition. The word came from Dante's poem about hell, which is where the second sense comes from, since an inferno is also a place of torment. The Italian original simply means hell. It always suggests scale and heat together, so a chip pan fire does not qualify.
1nouninfernoA large and dangerous fire.
“The warehouse was an inferno within minutes.”
An inferno is hell. Italian took Latin infernus, of the lower regions, as its name for the place, and the sense of a great fire is a figurative use of hellfire.
Latin
infernus — of the lower regions
Italian
inferno — hell
English, today
inferno
Built from
From 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