noun
etymological theory; etymology
Refers to a specific theory about the origin of a word, not the general study of etymology (語源学). Often used when discussing competing explanations for a word's history.
この語源説にはいくつかの異論がある。
There are several objections to this etymological theory.
彼は新しい語源説を発表した。
He proposed a new etymological theory.
語源 is the general term for 'etymology' or 'word origin', whereas 語源説 emphasizes a particular explanation or theory.
Compound of 語源 (etymology) + 説 (theory). The exact historical derivation is uncertain, but the components are transparent.