Si Collection, Middle Volume. Radical: Fire (huǒ). Kangxi stroke count: 15. Page 680, Entry 22.
According to the Rhyme Dictionary of the Guangyun (Guangyun), pronounced li. According to the Collected Rhymes (Jiyun), pronounced yu. The pronunciation is the same as yu. The Explaining Graphs and Analyzing Characters (Shuowen Jiezi) defines it as a great, flourishing light. In the Book of Odes (Shijing), Binfeng section, it is written: The orioles fly, their feathers shining brilliantly. The commentary notes that this refers to bright and vivid feathers. The Collected Rhymes (Jiyun) states it is identical to the characters ye and ye.
Furthermore, according to the Rhyme Dictionary of the Guangyun (Guangyun), yi yao refers to fireflies. In the Book of Odes (Shijing), Binfeng section, it is written: Fireflies moving in the night. The commentary notes that yi yao refers to phosphorescent light, and phosphorescent light is the firefly.
Additionally, according to the Tang Rhyme (Tangyun), the pronunciation is yang. According to the Collected Rhymes (Jiyun), the Rhyme Compendium (Yunhui), and the Correct Rhymes (Zhengyun), the pronunciation is yi, with the same sound as ni. Furthermore, according to the Collected Rhymes (Jiyun), the pronunciation is xi. The meanings are the same.