an outdoor bath, often at a naturally occurring hot spring

(linguistics) sound shift / (linguistics) sound shifts from Old Japanese to Modern Japanese, especially those which are preserved in historical kana usage.

perfect beauty with no trace of artifice; flawless / innocent, simple-minded

(mathematics) A Chinese system of algebra for polynomial equations created in 13th century

weather

stick; apply; paste

lightning / electricity

genius

astronomy

score, grade, mark