whereat

/wɛrˈæt/
adverb
  1. At which; upon which (used in formal or literary contexts to refer back to something previously mentioned).
    • The king raised his hand, whereat the guards immediately fell silent.
    • He made a rude comment, whereat she left the room in anger.
    • She explained the problem, whereat everyone nodded in understanding.
Synonyms
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