An election held to fill a political office that has become vacant between regularly-scheduled elections.(noun)
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Use "byelection" in a sentence
"It's clear that the byelection was another boost for ourselves and Ukip, and another bad day for the "big three""
"When Brown decides to call the byelection will give us an insight into how confident he feels about his own position in the party and what hope he holds out for this autumn relaunch turning things around for his government."
"Council now has 60 days to either appoint someone to fill the seat or call a byelection, a move that would cost more than $125,000."