AbstractFrom a cognitive linguistic perspective, this article delves into the polysemy between the English termsour and its Chinese counterpart suan. The research aims to achieve two key objectives: (1)To explore the similarities and differences in the polysemy of sour in English and suan inChinese; (2) To identify the cognitive mechanisms that motivate the semantic expansion of sour in English andsuan in Chinese. To this end, 《汉语大词典》 (the Great Chinese Dictionary), The Oxford English Dictionary (OED), the British National Corpus(BNC), and the Centre for Chinese Linguistics (CCL) Chinese-English Parallel Corpus were used. The dictionaries are utilized toexplore the polysemy of sour and suan, while the BNC and CCL Chinese-English Parallel Corpus areemployed to investigate the cognitive mechanisms underlying the semantic extensions of the selected terms. Theoretically, thisarticle draws upon the conceptual metaphor and metonymy theory proposed by Lakoff and Johnson. The findings reveal significantsemantic overlap between sour in English and suan in Chinese, yet notable distinctions remain.This study has implications for vocabulary teaching as well as cross-linguistic and cross-cultural communication.