Tang Yun (a classic dictionary) notes the pronunciation is gai (falling tone). Shuowen Jiezi (Explanation of Simple and Compound Characters) explains it as deep and solid. The character structure is composed of two parts and the shell radical. The shell represents a solid, valuable item. Also, Jiyun (Collective Rhymes) notes the pronunciation is xie (falling tone). The meaning is the same. Note: Wuyin Jiyun (Five Tones Collective Rhymes) writes the character as a variant, and Zihui (Collection of Characters) followed this usage, but it is now corrected. The variant form is written with the character for hearth on the left and the shell radical below. Also.