容積比: volume ratio

篳篥: a cylindrical double reed wind instrument used in the gagaku music of Japan

飛竜: a wyvern / 飛龍: a "flying dragon" (shogi piece)

百日の説法屁一つ: “a hundred days of sermonizing, one fart” → a metaphor for how extreme effort something that one has put great effort into can come to nothing after even a slight mistake, much as a hundred days of serious spiritual study can be lost to the winds

平日: weekday; the "say" radical (曰)

(bookstore jargon) stacking books on top of each other, facing upwards

tideland

Short for ひやけサロン.

to sit on the fence; to be opportunistic

平地: flat land