This document provides an introduction to lexicology, which is the study of words. It discusses different types of word formation processes including affixation, compounding, blending, clipping, conversion, backformation, acronyms, onomatopoeia, and eponyms. Specific examples are given to illustrate each word formation process. The document concludes by noting that lexicology also examines the origins, historical changes, semantic changes, lexical semantics, idioms, and dictionaries of words.