Even though Summary of Chinese Historical Lexicology by Jiang Shao Yu is the most important theoretical achievement both of Chinese lexicology in general and of the contemporary one, there are some points to be discussed in a more detailed manner. Of them is that of the absolute synonym such as ‘zhou’ (舟) and ‘chuan’ (船). Considering it worth discussing, this paper holds that ‘chuan’ (船) began in the early and middle stage of Warring States Period, not in the late one of it. For, the use cases of ‘chuan’ (船) in the literature of the middle and late stage of Warring States Period increased, and the frequency ratio of ‘zhou’ (舟) and ‘chuan’ (船) changed in those stages. They are general synonyms rather than absolute synonyms because the former means not merely the boat but also the big boat as in ‘long zhou’ (龍 舟), ‘da zhou’ (大舟) and ‘ju zhou’ (巨舟). Instead of ‘zhou’ (舟) itself referring to the big boat, the meaning of ‘zhou’ (舟) is still the boat, and ‘zhou’ (舟) and ‘chuan’ (船) constitute synonyms in the meaning of the boat, which indicates that the meaning of size comes from its modifying elements.