《爾雅》既是通經要籍，亦是我國最早的詞典，歷代注家，多不勝數。然而，前人注釋的觀念與方法均有可商之處。第一，他們多以求同為訓釋字詞的終極目標，即只求被釋詞有釋詞之義，證明二者義同，工作便算完成，但如「帝」、「公」之為「君」，單言其義同，於分辨詞義方面，作用不大，因為這難以突顯字詞的獨特含義。第二語料蒐集不足。這在一定程度上是受到上述注釋觀念的影響，既然只為求同，那麼，但舉數例以證明釋詞與被釋詞義同即可。問題是：它們在甚麼情況下義同？義同的程度又如何？二者存在怎樣的意義關係？要解決這些問題，必須全面考察字詞的用例，才能有周延的結論。本文之作，是為了探求《爾雅》這組同義詞的意義差別，並希望為「同義為訓」這個典型的訓詁方法做一些深化的工作。

　　　　　The Erya is the earliest thesaurus in China, and a brilliant pleiad of past scholars and annotators have attempted to study it. Nevertheless, their commentaries seem to be inadequate in explaining the lexicon in the Erya. To begin with, the ultimate aim of their commentaries was to prove that the terms in the Erya possess a synonymous relationship with their respective explanations. In order to do so, these scholars concentrated on a few sentences that contained evidence of such synonymous relationship and built their commentaries upon them. For example, they illustrated that "di" and "gong" both possess the meaning of "jun." However, this methodology not only fails to explain the individual and unique meaning of the three terms, it also relies on a thin basis of evidence that is insufficient to point out the following: (1) Under what circumstances are these terms considered synonymous? (2) To what degree can they be regarded as synonymous? (3) What kind of semantic relationship exists between these terms? To resolve these issues adequately, the author believes that it is essential to find out the differences between the unique meanings of each term. This can be achieved by carefully studying all their usages, which can then be used as a corpus for an in-depth analysis. The aim of this article is to illustrate how this methodology can be applied to the study of Chinese semantics.