whereupon
UK: ˌweərəˈpɒn | US: ˌwerəˈpɑːn
conj. immediately after which; at or after which time
adv. in consequence of which; upon which
The word "whereupon" is a compound of "where" (Old English hwǣr, meaning "at what place") and "upon" (Old English uppan, meaning "on top of"). It emerged in Middle English as a conjunction/adverb to denote a sequential or consequential relationship ("at which point" or "as a result of which"). The fusion preserves the spatial logic of "where" (locative) + "upon" (temporal/causal), reflecting how physical positioning metaphorically extended to temporal/causal connections.
He finished his speech, whereupon the audience applauded.
She signed the contract, whereupon the deal was finalized.
The alarm rang, whereupon everyone evacuated the building.
The judge ruled in her favor, whereupon the defendant appealed.
The sun set, whereupon the streetlights automatically turned on.