古往今來，談論昭穆之制者極夥，但直接解說「昭穆」二字取義的卻不多見。而在各種解說「昭穆」含意的說法中，以現代學者的論述最為詳細。本文旨在綜論古今學者的不同說法，包括宋代的陸佃、朱熹；現代的李衡眉、唐友波、黃光武等人之說，指出其疏漏之處，並從訓詁角度切入，再結合先秦的哲學觀念，為「昭穆」之命名取義尋求一個合理的解釋。實際上，在說解「昭穆」二字時，段玉裁早就指出，昭為明，穆為幽，更明確地把「昭穆」與「陰陽」配對起來。而且，根據古訓，「明」、「幽」與「長」、「幼」概念相通，可見「昭穆」即「陰陽」之代稱。放在固有「數成於三」的哲學觀念來看，「昭穆」原指父子間陰陽相對相轉的關係而已。父子異昭穆，猶陰陽相間，至孫而復為昭（陽），完成一個循環，由是而父昭子穆，生生不息，以至無窮。因此，昭穆是陰陽說的轉化，是陰陽說的產物。陰陽思想體現於人倫叫「昭穆」，應用在十干的區別上則稱「剛柔」。

There have been numerous discussions since antiquity on the zhaomu昭穆 system of inheritance, yet little has been said on the meaning of the term zhaomu itself. The present article examines the few existing explanations, including those by Lu Tian陸佃 and Zhu Xi朱熹 of the Song dynasty, as well as in-depth modern studies by Li Hengmei李衡眉, Tang Youbo唐友波and Huang Guangwu黃光武, and attempts to develop a plausible account of the term from philological and philosophical perspectives. Indeed, the Qing scholar Duan Yucai段玉裁 has already pointed out that zhao and mu signify light and darkness respectively, corresponding to the yinyang陰陽 dichotomy. Ancient exegeses similarly relate light-darkness to old-young. Thus, zhaomu is really just another name for yinyang. Interpreted in the philosophical view of "shu cheng yu san" 數成於三 (number established at three), zhaomu originally refered to the revolving paternal relation-the father (zhao) gave birth to the son (mu), who in turn bore the grandson (zhao), completing a cycle. Zhaomu is then a manifestation of the yinyang notion applied to Chinese ethics, analogous to the way gangrou剛柔(strong-weak) is applied to the ten heavenly stems.