Yes application is a software developed to parlicular client for his requirements. whereas a product is for all the people needed.
But In practicle application Testing and Product Testing are same.
1] If someone ask about your project which you have tested that time our reply is our project name--- means our product -- Right?
2] now if someone ask on which application do you have experience regarding Testing--- our reply is Application by which our product or project has made example JAVA ASP..... Right?
These two sentence shows that our answer is diffrent but meaning is same because we have tested the same Project which is our product and is developed in JAVA or ASP or any other application. So Application testing and Product Testing are same thing...
Amit Hambarde