説(せつ) せつ noun theory, opinion, view academic 1. theory, hypothesis An explanation or proposed explanation for something, often in academic or scientific contexts. 進化論(しんかろん)はダーウィンが唱(とな)えた説(せつ)だ。🔊 The theory of evolution is a theory proposed by Darwin. いろいろな説(せつ)があるが、真実(しんじつ)はまだわからない。🔊 There are various theories, but the truth is still unknown. 新(あたら)しい説(せつ)が発表(はっぴょう)された。🔊 A new theory was announced. 2. opinion, view A particular viewpoint or belief held by someone. 彼(かれ)の説(せつ)によると、地球(ちきゅう)は温暖化(おんだんか)している。🔊 According to his view, the Earth is warming. 彼女(かのじょ)の説(せつ)では、原因(げんいん)は別(べつ)にある。🔊 According to her view, the cause lies elsewhere. 専門家(せんもんか)の間(あいだ)でも説(せつ)が分(わ)かれている。🔊 Even among experts, opinions are divided. 説(せつ) is used for theories, hypotheses, and opinions. It often appears in compounds and with particles.Common patterns〜という説(せつ): the theory that ~説(せつ)を唱(とな)える: to propose/advocate a theory説(せつ)によると: according to the theory/view〜説(せつ): ~ theory (suffix)Compounds仮説(かせつ): hypothesis学説(がくせつ): academic theory定説(ていせつ): established theory異説(いせつ): different/dissenting opinion俗説(ぞくせつ): popular belief, folk theory general Added 2026.1.13 8:49 · Revised 2026.9.2 11:55 00000/00360_setsu