What does 大戦 mean?
大戦 is a Japanese noun meaning “great war, great battle” in English. It is written as 大戦 in kanji, たいせん in hiragana, and taisen in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
あの家の繁栄は大戦中からのことだ。
The prosperity of the family dates from the Great War.