Acceptance testing means toget acceptance from the 
client.
   Two types 1.alpha:almost all near the completion of the 
dovelopment of the project the endusers are conduct this 
testing before going to the delivery.
 
              2.beta:this testing is conducted by endusers 
after delivery the project.

it refers to to the client requirment

ACCEPTANCE TESTING:- Its an activity of Testing whether the 
application is acceptable or not.

Acceptance Testing is one of the last phases of testing 
which is typically done at the customer place.

This is Done as:

Alpha Testing:
Testing is performed by the end users within a company but 
outside the development group.

Beta Testing:
Testing is performed by a subset of actual customers 
outside the company.

testing will demonstrate that the equipment or system 
operate in according with the functional specification and 
detailed design documents