This chapter explores the construction and structural analysis of lexical semantics. It examines the constituent units of lexical semantics—including sense, plereme, sememe, morpheme meaning, and plereme cluster—while analyzing their subtle distinctions and theoretical controversies. By outlining the theoretical foundations, procedures, and methods of sememe analysis, the chapter highlights its significance in revealing lexical semantic structures, describing lexical feature attributes, facilitating semantic clustering, and constraining lexical combinations.