The so-called rhyme in poetry is roughly equal to the so-called vowel in Chinese Pinyin. When a Chinese character is spelled with pinyin letters, it usually has initials and finals. For example, the word "male" is spelled g not ng, where g is the first letter and ng is the last letter. The first letter is always in front and the vowel is always in the back. Let's look at the words "Dong", "Tong", "Long", "Zong", "Cong" and so on. Their vowels are all long, so they are homophones. Any rhyming word can rhyme.
The so-called rhyme means putting two or more rhyming words in the same position. Generally, rhyme is always placed at the end of a sentence, so it is also called "rhyme foot".
The ancients rhymed according to rhyming books. The so-called "official rhyme" of the ancients is the rhyme book promulgated by the court.