In the Book of Rhymes (Guangyun), it is pronounced xi (level tone). In the Collection of Rhymes (Jiyun) and the Meeting of Rhymes (Yunhui), it is pronounced xi (level tone). The pronunciation is the same as the character yi (level tone). It means dust. Additionally, in the Book of Rhymes (Guangyun) and the Correct Rhymes (Zhengyun), it is pronounced yi (falling tone). In the Collection of Rhymes (Jiyun) and the Meeting of Rhymes (Yunhui), it is pronounced yan (rising tone) followed by yi (falling tone) [Note: simplified to reflect the resulting syllable: yi (falling tone)]. The pronunciation is the same as the character yi (falling tone). The meaning is the same.