In simple word clipping path stands for the layering path which functionally defines image transparency which people used for printing purpose and can be transferred into other program.
But if we want to define it in details then clipping path stands for binary (on/off in binary mode) operations of changing or removal of layering path which can be patterned in single layer or within multiple layer. Every single or multiple layer can be defined as indefinite clipping path.
How clipping path is useful can be noted with a simple example: Suppose your son is working in a class project where he want to use batman as one of your family member graphically, now you are searching for batman image but can’t find it without background, but your son want to add batman in your photo album, how you can do it? You can take clipping path service where a clipping path expert manually remove background and collect batman image without any damage and place it with your family member in such manner that everybody become astonished to see that batman is sitting beside you, amazing isn’t it!