On the Diachronic Substitution of "吃" for "食"

食(shi) is generally used in ancient Chinese to express the meaning of 吃(chi).喫(chi) as a verb clearly expressing the meaning of 吃 started from the Six-dynasty period.It usually appeared on the informal occasions and was not widely used in this way.喫 was used by more and more people since Tang Dynasty,but compared with 食,it was still scarcely used.In the later periods of Tang Dynasty and Wudai,喫 replaced 食 in colloquial language and was used as 吃.Since Song Dynasty,喫(吃) developed rapidly and became prevalent than 食.This paper makes a study of the diachronic substitution of 吃 for 食 from the angle of lexis history.