Account abstraction is covered in full in the entry Account Abstraction Standard, which explains the standards, how they work and their trade-offs. This page gives a short definition and explains why the two names exist.
Account abstraction is the idea that a blockchain account should be governed by programmable rules rather than by a single private key. On networks such as the Ethereum blockchain, the traditional wallet is an externally owned account: whoever holds the key controls the funds, and losing the key means losing access. Account abstraction turns the account into a smart contract that can set its own conditions, such as several approvals for large transfers, daily spending limits, recovery through trusted contacts, or fees paid in a token other than the native coin.
"Account abstraction" names the general concept, discussed by Ethereum developers for years. "Account abstraction standard" usually refers to a specific technical specification that puts the concept into practice, most often ERC-4337, which delivered smart accounts without changing Ethereum's core protocol. Because most readers meet the concept through that standard and the wallets built on it, Money Wiki keeps the detailed explanation in one place under the standard's name.