Abstraction of a way through which show only necessary and essential fetures to the client of the object to the outside world. Means displaying what is necessary and encapsulate un-necessary thing to the outside world. Hide can be achieve through "Private access modifier". Abstraction shows what does the object can do instead of how does it works. This hide the working style of an object.and only shows the info of object in understandable manner.

http://www.c-sharpcorner.com/UploadFile/mkagrahari/introduction-to-object-oriented-programming-concepts-in-C-Sharp/

Abstraction is properties which hide the implementation but it provide the services to user.