noun
closely contested constituency; highly competitive marketplace; battleground
Used for electoral districts with fierce competition, markets with many rivals, or any area of intense rivalry. The figurative sense 'battleground' is common.
この選挙区は毎回、与野党の激戦区になる。
This electoral district becomes a closely contested constituency between the ruling and opposition parties every time.
駅前に新しいラーメン店が次々と
New ramen shops are opening one after another in front of the station, making it a highly competitive marketplace.