轉都係借用悉曇嘅概念，取悉曇中梵文元音與輔音輾轉相拼之義。簡單來講，一轉就是一頁——即韻圖中嘅一圖。一轉中可以只包含韻書中嘅一韻（毋分聲調），都可以包含多達四個韻，分列四等，甚至五個韻——如「《韻鏡》外轉十三開的去聲欄」列有代、怪、祭、霽四韻，而入聲欄裏仲有一個「去聲寄此」嘅夬。
Zhuan is also borrowed from the concept of Si Tan, taking the meaning of the Sanskrit vowels and consonants in Si Tan. To put it simply, a turn is a page – a picture in a rhyme diagram. A ritual, it can contain only one rhyme in the rhyme book (regardless of tone), or it can contain as many as four rhymes, divided into four rhymes, or even five rhymes—for example, the "Rhyme Mirror" Outer Rotation Thirteen Open Voice-Removing Column lists the four rhymes of generation, strangeness, sacrifice, and thunderbolt, and there is also a "Voice-Removing Voice" in the Voice-incoming column.