noun, noun or participle which takes 'suru', transitive verb
detailed explanation; minute exposition
Rare, formal noun or suru-verb meaning a very detailed, point-by-point explanation. Mostly found in older or highly formal writing.
この問題については、後ほど縷説する予定です。
I plan to give a detailed explanation of this matter later.
Compound of 縷 (ru, 'thread' or 'detailed') and 説 (setsu, 'explanation'). The exact historical derivation is uncertain, but the kanji suggest a 'thread-like' detailed exposition.