wealth: [13] The now virtually defunct weal [OE] meant ‘welfare’, and also ‘riches’; it was descended from prehistoric West Germanic *welon, a derivative of the same base as produced English well. The abstract-noun suffix -th was added to it in early Middle English to produce wealth. This also originally meant ‘welfare, well-being’ as well as ‘riches’, a sense which now survives only in the compound commonwealth [15]. => well[wealth etymology, wealth origin, 英语词源]
mid-13c., "happiness," also "prosperity in abundance of possessions or riches," from Middle English wele "well-being" (see weal (n.1)) on analogy of health.