It often amazes me that FITNESS is a multi billion dollar industry... Yet an excellent, universal and concise definition of fitness is difficult to nail down.
Simply ask a person participating in a physical exercise program, and even someone in the fitness industry for https://flatbellyshake.com/ - continue reading this - that matter, to provide you with an apparent meaning of health and fitness.
You'll more than likely be welcomed with the "deer found in the headlights" gaze accompanied by nonsensical stammering.
If you do get a remedy, it'll most probably be slanted toward the particular proficiency of the person asked.
For example...

A marathon runner is going to define fitness in conditions of cardiorespiratory and muscular endurance... A power-lifter is going to define fitness in conditions of absolute strength... A bodybuilder is going to define fitness in terms of muscle size as well as definition... etc.
But the vast majority of people participating in a physical fitness program are not professional athletes worried about the improvement of just one physical ability.
Therefore, basing your definition of fitness on a single certain physical ability doesn't lead to a universal definition of health and fitness.