Analyzing English: An Introduction to Descriptive Linguistics

"Lexicology deals not only with simple words in all their aspects but also with complex and compound words, the meaningful units of language. Since these units must be analysed in respect of both their form and their meaning, lexicology relies on information derived from morphology, the study of the forms of words and their components, and semantics, the study of their meanings. A third field of particular interest in lexicological studies is etymology, the study of the origins of words. However, lexicology must not be confused with lexicography, the writing or compilation of dictionaries, which is a special technique rather than a level of language studies. . .
"The essential difference between syntax and lexicology is that the former deals with the general facts of language and the latter with special aspects. . . Syntax is general because it deals with rules and regularities that apply to classes of words as a whole, whereas lexicology is particular because it is concerned with the way individual words operate and affect other words in the same context. Although borderline cases do exist in both lexicology and syntax, e.g. in the case of 'grammatical' or 'function' words, the distinction between the two levels is fairly clear.".