Defect: Defect is the problem or error found in the application while testing, which is unnecessary or which my hindrant to the other functions of the application.
Enhancement: Its the additional feature or functionality found and added to the application as desired by the end user/real word customer or tester during the testing process.
Defect: It is some unexpected fault in the application because of that i wont work proper.means it has a some error that make it a faulty one.
Enhancement: It is a way to introduce some extra productive qualities into the existing application while testing for the user requirement and satisfaction.