An interface is similar to a class, but it provides a specification rather than an implementation for its members. An interface contains definitions for a group of related functionalities that aclass or a struct can implement.

Delegates: A delegate dynamically wires up a method caller to its target method. There  are two aspects to a delegate: type and instance.Events: Events are pairs of methods, appropriately decorated in IL to tie them together and let languages know that the methods represent events. The methods correspond to add and remove operations.

1. static members are one per class but non-static members are one per instance.
2. static members are accessed by their class name which encapsulates them, but non-static members are accessed by object reference.
3. static members can't use non-static methods without instantiating an object, but non-static members can use static members directly.
4. static constructor is used to initialize static fields, but for non-static fields normal instance constructor is used.

A collection is a set of similarly typed objects that are grouped together. The .NET Framework provides a standard set of types for storing and managing collection of objects.

Generics type Parameter
In a generic type or method definition, a type parameters is a placeholder for a specific type that a client specifies when they instantiate a variable of the generic type
GenericList<float> list1 = new GenericList<float>();