etymologeek.com dictionary
English word brontomancy (meaning "divination by thunder") comes from English bronto- (thunder), which itself derives from Ancient Greek βροντή (also meaning thunder), and -mancy (prophecy), which itself derives from Ancient Greek μαντεία (meaning prophecy or divination)..

Brontomancy etymology history?

Brontomancy detailed word origin explanation

Dictionary entryLanguageDefinition
bronto- English (eng) Thunder.
-mancy English (eng) Divination.
brontomancy English (eng) (rare) Divination by thunder.

Words with the same origin as brontomancy

Descendants of -mancy
aeromancy amniomancy anthracomancy arithmancy astragalomancy astromancy belomancy bibliomancy ceromancy chiromancy cyclomancy entomomancy hieromancy logomancy molybdomancy oneiromancy ornithomancy psychomancy selenomancy sideromancy spodomancy tasseomancy tephramancy xylomancy zoomancy
Descendants of bronto-
brontophobia brontoscopy