I would agree with you that it is very difficult to define the essence of tennis in comprehensive,and consise way.One has to be very knowledgeable and experienced to be able to define it starting from nemerous details, and reach simple and obvious definition.
I would not agree with you that there are several definitions.There is just one right definition which would cause following reaction,"That is it.It is so obvious, and it was in the back of my mind, just I could not articulate it."
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