What does 説 mean?
説 is a Japanese noun meaning “theory” in English. It can also be translated as “opinion, rumour” depending on context. It is written as 説 in kanji, せつ in hiragana, and setsu in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
あなたがなんと言おうと、私はやはりその説が正しいと思う。
For all you say, I still believe in the truth of the theory.