A complementizer, as used in linguistics (especially generative grammar), is a syntactic category (part of speech) roughly equivalent to the term subordinating conjunction in traditional grammar. For example, the word that is generally called a complementizer in English sentences like Mary believes that it's raining. The term "complementizer" was apparently first used by Rosenbaum (1967). The standard abbreviation for complementizer is C. The complementizer is widely held to be the syntactic hea… (More on Complementizer)