The word antediluvian means:
- Ancient or antiquated
- Extremely dated
- Pertaining or belonging to the time period prior to a great or destructive flood or deluge.
- (biblical) Pertaining or belonging to the time prior to Noah’s Flood.
It comes from the Latin ante- (before) and dīluvium (flood), which comes from dīluō (I wash away) and -ium (a suffix used to form abstract nouns), from dis- (apart, reversal) and lavō (I wash) [source].
The English word deluge (a great flood or rain), comes from the same Latin roots, via the Old French deluge (a large flood), as does the word diluvium (an inundation of flood, deluge; a deposit of sand, gravel, etc made by oceanic flooding) [source].
Other words from the same Latin roots include déluge (The Flood, deluge) in French, diluvio (deluge, downpour) in Spanish, díle (flood, deluge, torrent) in Irish, and dilyw (flood, deluge, destruction, ruin) in Welsh [source].
In Scottish Gaelic dìle [dʲiːlə] can refer to a deluge or flood. The phrase an dìle bhàite means heavy downpour or pouring rain, and the equivalent of it’s raining cats and dogs is tha an dìle ‘s an deàrrsach ann or tha an dìle bhàite ann an ceartair. As an adjective it means endless, for example gu dìlinn means “until the end of time” [source].
Another word for flood is inundation, which comes from the Old from inundacion (flood), from the Latin inundātiō (inuncation, overflowing, flood, crowd of people), from inundō (I overflow, inundate, flood) from in- (in, within, inside) and undō (I surge, flow), from unda (wave, billow) [source].
Undulate and undulation come from the same root, as does und, an obsolete word meaning wave, or in heraldry, a billow- or wave-like marking [source].
The word flood comes from the Middle English flod (river, lake, ocean, flood, rising tide), from the Old English flōd (flowing of the tide, river, stream, water, flood, deluge), from the Proto-Germanic *flōduz (river, flood), from the PIE *pléh₃tus (overflow, deluge), from *pleh₃(w)- (to flow, run) [source].
Cognates in other languages include flod (river, flood, high tide) in Danish, Norwegian and Swedish, Flut (flow, flood, hight tide) in German, and vloed (flood, current) in Dutch [source].
