This chapter discusses the notion of categories within the domain of syntax. It says that one has an idea of what nouns, verbs, adjectives, and prepositions are. The chapter presents the issues that arise, however, when specific questions are raised concerning these categories. A noun is the name of a person, place, or thing. However, saying that categories are well known does not mean that they ... [Show full abstract] are well understood. The discussion is placed within the context of natural language data that have been used to defend or refute particular claims. The chapter also says that categorical distinctions exist in all languages at the most basic level-the lexical entry. While this is the main goal of the chapter, its secondary goal is to develop a methodology that uses natural language data to answer questions concerning the status of categories in syntax. The chapter defends a need for categorical information in lexical entries using data from St'át'imcets and Malagasy.