Formed from 'wele' (well-being) + '-th' — originally 'general prosperity,' narrowed to 'having lots of money.'
An abundance of valuable possessions or money; the state of being rich.
From Middle English 'welthe' (well-being, prosperity), formed from 'wele' (well-being, happiness) + '-th' (abstract noun suffix), on the model of 'health.' 'Wele' comes from Old English 'wela' (wealth, well-being), from Proto-Germanic *walō (well-being), from PIE *wel- (to wish, to will, to choose). The word originally meant 'well-being' in general, not specifically money — the shift to purely material prosperity is a later narrowing. Key roots: *wel- (Proto-Indo-European: "to wish, to will, to choose").
'Wealth' was formed on the model of 'health' — both are Old English/Middle English creations using the '-th' suffix to make abstract nouns. 'Health' is the state of being 'whole' (hale); 'wealth' was originally the state of 'being well' (wele). Money was only one component of wealth; happiness and health were the others.