Wu Collection, Lower Volume Radical: Stone (shí) 磤 Kangxi Stroke Count: 16 Page 835, Entry 31 Pronounced yǐn (third tone) Sound of thunder. As seen in the Rhapsody on Jingfu Hall (Jingfu dian fu) by He Yan: The sound roars like thunder. Also a variant form (yīn) as found in the Book of Odes (Shijing), Shao nan section: The thunder rolls.