How to say "bye-election" in Japanese

• 補選ほせん
  nounCovers the by-election sense: an election held to fill a legislative seat that falls vacant mid-term. A two-character abbreviation of 補欠選挙, it is the compact form, typical of news reports.
• 補欠選挙ほけつせんきょ
  nounAlso covers the by-election sense, an election held to fill a legislative seat vacated mid-term; it is the full form of 補選. Use it when you want the term spelled out rather than shortened.

Both words cover the same sense of 'bye-election' — an election held to fill a legislative seat vacated mid-term — and both are less common choices; they differ only in form: 補欠選挙 is the full term, 補選 its abbreviation.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 補選ほせんspecial election
• 補欠選挙ほけつせんきょspecial election