The "diamond operator," represented as <> in programming, is a feature in languages like Java that simplifies the instantiation of generic classes. It allows developers to omit the type parameters on the right side of the assignment, making the code cleaner and easier to read. For example, instead of writing `new ArrayList<String>()`, you can simply use `new ArrayList<>()`. This operator helps reduce redundancy and enhances type inference, allowing the compiler to automatically determine the type based on the left-hand side. It is particularly useful in collections, such as List or Map, where specifying the type can become cumbersome.