We talked about declare and declaim earlier, and now we come to proclaim.  Generally, think of proclaim as being like declaim, but without any special relationship with the compiler.  In a normal context, proclaim only has an effect once the form containing it is executed, and doesn’t do anything at compile time.  The programmer might use this in a situation where declaration specifiers have to be handled at runtime, but the use cases are, in my experience, rare.