WordReference Random House Learner's Dictionary of American English © 2020 where•up•on /ˌhwɛrəˈpɑn, -ˈpɔn, ˌwɛr-; ˈhwɛrəˌpɑn, -ˌpɔn, ˈwɛr-/USA pronunciation
conj. WordReference Random House Unabridged Dictionary of American English © 2020
- upon what or which.
- at or after which:He'll surely try to get in touch with her, whereupon we'll spring the trap.
(hwâr′ə pon′, -pôn′, wâr′-; hwâr′ə pon′, -pôn′, wâr′-),USA pronunciation conj.
- upon what or upon which.
- at or after which.
- [Archaic.]upon what?
- Middle English wherupon. See where, upon 1300–50
Collins Concise English Dictionary © HarperCollins Publishers::
whereupon /ˌwɛərəˈpɒn/ sentence connector
- at which; at which point; upon which
'whereupon' also found in these entries: