Definition: In the context of software development, a stylebook is a collection of commonly used styles or coding conventions for a particular programming language. It serves as a reference guide and template for developers to follow when writing code in that language. The stylebook typically includes predefined sets of rules, syntax patterns, and guidelines for syntax, formatting, indentation, variable naming conventions, etc. These rules are designed to make the process of writing code more efficient and readable, especially when working with complex or specialized programming languages like