《老子》雖僅五千言，其相關於「道」的哲學義涵卻極其豐富，它們成就了《老子》哲學在後世的多元開展。不同時代不同文化或學術性格的個人或族群，對於《老子》「道」的義涵常有不同的理解與詮釋。就漢代道家學者或文獻對於「道」的理解而言，往往不是「氣」，就是「術」。凡著重推闡「道」崇高、虛無的本體質性、至高理則，或體道者高妙的入道情境時，都因沿《老子》「道」的原稱。凡涉及「道」的生成與「身」之修養時，則多引介「氣」來替換「道」，解證其生成與修養之理。一旦涉及漢人甚為重視的治政、經世之論時，則往往直接以「術」稱代「道」。而當由道家轉入道教，由哲學轉入宗教時，「道」則被落實成為方便持守的「誡」，或可以依皈膜拜的神靈─太上老君。

The book of Lao-tzu comprised just five thousand words; however, it had bountiful implications for ＂Dao＂, which inspired numerous followers to diversify its philosophical conception. People in different ages, of different cultures, or with different academic characters had diverse understandings of and put distinct interpretations on the connotation of ＂Dao＂. In the Han Dynasty, documents about Daoism often referred it to ＂Chi＂ (life energy) or ＂Shu＂ (art). In other words, scholars of the Han dynasty who advocated the pure nature of being, the supreme doctrine and the subtle perception of Dao would replace the term ＂Dao＂ with ＂Chi＂. And scholars who valued the political statecraft would refer ＂Dao＂ to ＂Shu＂; that is, the art of governance. However, there was another sect that transferred the philosophical Daoism into a religious practice. In this way, ＂Dao＂ became a commandment and Lao-tzu was divinized to be Taishang Laojun-the Grand Supreme Elderly Lord.