Which keyword is used to define a function in Kotlin?

In Kotlin, the keyword used to define a function is "fun." This keyword is a critical part of the language's syntax and is employed to initiate the declaration of a function. The structure generally follows the format: fun functionName(parameters): ReturnType { // function body }.

Using "fun" clearly indicates the purpose of the statement, making the code easier to read and understand for anyone familiar with Kotlin. This design choice aligns with Kotlin's philosophy of being a concise and expressive language, enabling developers to convey ideas simply and directly.

The other options presented do not correspond to the correct syntax for defining a function in Kotlin. "func," for instance, is used in some other programming languages (like Swift) but is not recognized in Kotlin. "function" and "newFunction" do not follow Kotlin's conventions for function declaration and lack the necessary keyword that denotes function creation in the language. Understanding the significance of "fun" is essential for effectively writing and organizing functions in Kotlin.