Interpretation of Yan in Chinese Idiomatic Expression Yan Gui YuHao

Ever since Wang Yinzi in his book Interpretation of Classics explainsthat yan stands for words or phrases, yan has been thought to be an auxiliary word without any exact meaning in many reference books. Based on some related document and phonology, the author believes that yan should be a combination of twowords - wo + yan, its meaning is hence. After the Qing dynasty, yan has beenconverted into an auxiliary word with no exact meaning.