1530s, "sufficient estate," from Anglo-French assetz, asetz (singular), from Old French assez "sufficiency, satisfaction; compensation" (11c.), noun use of adverb meaning "enough, sufficiently; very much, a great deal," from Vulgar Latin *ad satis "to sufficiency," from Latin ad "to" (see ad-) + satis "enough," from PIE root *sa- "to satisfy."
At first a legal word meaning "sufficient estate" (to satisfy debts and legacies), it passed into a general sense of "property," especially "any property that theoretically can be converted to ready money" by 1580s. Figurative use from 1670s. Asset is a 19c. artificial singular. Corporate asset stripping is attested from 1972.