C# Language Specification

The dynamic type

The type dynamic has special meaning in C#. Its purpose is to allow dynamic binding, which is described in detail in §7.2.2.

dynamic is considered identical to object except in the following respects:

• 
  Operations on expressions of type dynamic can be dynamically bound (§7.2.2).
  
• 
  Type inference (§7.5.2) will prefer dynamic over object if both are candidates.
  

Because of this equivalence, the following holds:

• 
  There is an implicit identity conversion between object and dynamic, and between constructed types that are the same when replacing dynamic with object
  
• 
  Implicit and explicit conversions to and from object also apply to and from dynamic.
  
• 
  Method signatures that are the same when replacing dynamic with object are considered the same signature
  

The type dynamic is indistinguishable from object at run-time.

An expression of the type dynamic is referred to as a dynamic expression.

5.