The term 'Rules of Sentence Structure' is often used interchangeably with the term 'Syntax' (6 letters). Syntax is a branch of linguistics that studies the structure of sentences in a language. It looks at how words are arranged to create phrases, clauses, and sentences. Syntax also examines the rules that govern the formation of sentences, such as word order, verb tense, and punctuation. By understanding syntax, one can better understand the meaning of a sentence and how it is constructed.