We all think we know what wealth is, but sometimes the "obvious" misses the mark.
Asking "what is wealth?" seems needless because we all know what wealth is: never having to work again, endless leisure, endless consumption of the "good things of life," being waited on hand and foot, luxurious belongings, vehicles and homes, a life of travel and sport, trust funds, stacks of secure gold, and so on.
All this is "obvious," but is that certainty illusory? There are many people with $2 million in net worth, a significant number with $20 million, and more than a few with $200 million. All would be considered wealthy by the average household earning $63,000 annually with a total net worth of less than $100,000, not to mention the 61 million American wage-earners who pull down less than $20,000 a year who own negligible net worth.
Those with a mere $2 million may not reckon themselves wealthy, if their eyes are fixed on those with $20 million. But if a wealthy person suddenly discovers they are riddled with fast-growing cancer, then they quickly lose interest in financial wealth except in terms of what medical treatment it can buy.
There really isn't much more modern medicine can do for someone worth $200 million than it can for someone worth $2 million; once one's life and health are at risk, then conceptions of "wealth" are drastically reordered: health is wealth, and nothing else matters.
Once lost, health is difficult to restore, and financial wealth is no longer the key metric. The graveyards are full of extremely wealthy people who died "before their time."