日語方位詞「西」與其他語彙複合、像「西口」、「西日本」是表達「方位」或者「位置」等基本語義之外、受到人們的生活體驗以及各國不同的語言文化、宗教思想等的影響之下、產生像「西曆」、「西方淨土」和「東西東西」等許多衍生用法。也就是方位詞「西」形成了所謂「多義表現（polysemy。国広1994：22－44）」。這些表現之間究竟有何語義關係？基本義是如何地延伸出許多衍生義等問題、成為本論文探討的重點。本論文是以認知語義學的觀點、來分析中日兩國語言方位詞「西」的多義構造。研究方法如下：（1）首先從兩國語言的辭典與語料庫中收集語料。然後（2）對方位詞「西」的所有衍生用法進行分類檢討、以確定實際共時狀態下之使用分布及語義範疇。接著（3）對方位詞「西」的各項用法進行比較、也參考語源辞典之解釈、以歸納確定「西」之最核心基本義的語義。之後（4）分析基本義與衍生義之間語義關係是否具有「類似性」、「隣接性」、「包摂性」等特性、並且以「隱喻、換喻、提喻」等譬喻的概念、來解釋基本義與衍生義之間的語義延伸。最後（5）用多義語義網絡圖來整理方位語「西」的多義構造、針對方位語「西」的基本義和衍生性之間的語義關係進行解釋、以提供日語教學與學習的參考。

This paper tried to analyze the polysemy structure of ”west” as a noun of locality, which is interpreted as ”nisi” in Japanese and ”xi” in Chinese from perspective of cognitive semantics. Research methods this paper adopted were as the followings: (1) Collecting texts from dictionaries and text corpora of Japanese and Chinese. (2) Sorting out derivations of ”west” as a noun of locality in order to understand its usage coverage and semantic range in synchronic reality. (3) Comparing fundamental usages of ”west” as a noun of locality, as well as generalizing its fundamental semantic features referring to explanations from etymology dictionary. (4) Analyzing fundamental meaning and derivative meaning not only to testify features i.e. similarity, proximity, or hyponymy, but also define the semantic extensions in-between, regarding concepts of cognitive metaphor, such as metaphor, metonymy, and synecdoche. (5) Summarizing polysemy structure of ”west” as a noun of locality based on semantic network so that clarifications are made between its fundamental meaning and derivation semantic interaction which can be used as future references for teaching and learning Japanese.