Xinhua Dictionary (Commercial Press, 1980 edition), p. 930: Ye Xier é and QIA Chang refer to the harmony of sounds. Ye Sheng | Ye Yun. ("Heqia", ancient pinyin, means "Heqia". )
Actually, let's take a look at it now. "Xie" actually means "harmony". There is an explanation of "harmony" in Xinhua Dictionary. Therefore, "Ye Xun" in the ancient poem Gepu means "Xie Xun" and "Harmony Xun". It was a special language of ancient people, and now it means "oath"
Therefore, Ye Yun means rhyme, Ye means rhyme and Ye Ping means rhyme.
Ye Erxu is more complicated, sometimes it means "two consecutive Xu Xuyin" in one sentence, and sometimes it means "Xu Xu's foot" in a poem, such as "seven words from beginning to end". It refers to the "seven laws" in the seven laws. The first sentence is "even" and the last sentence is "even". It depends on the second word of the first sentence and the penultimate word of the last sentence. Because the first sentence of the seven-character rhyme is "rhyme" and the last sentence is "rhyme". The last word doesn't count.
The sentence is equivalent to the current period. The completeness of sentences.
As a treasure in China culture, I hope you can keep studying.