Digital wallet
An app or service that holds card details, a balance or both and pays on the user's behalf — with a phone in the shop or a single click online.
The industry distinguishes two kinds. A pass-through wallet such as Apple Pay or Google Pay stores a token instead of the card number and forwards the purchase to the card network as an ordinary card payment. The merchant sees the card; the issuer sees the purchase. A staged wallet such as PayPal or Alipay is itself the payee. It pays the merchant, then charges the card or bank account in a separate transaction, and so knows more about both sides than anyone else in the chain.
The technology underneath is tokenisation plus either a secure element in the phone or HCE. The business underneath is data and the customer relationship, which is why banks have watched with mixed feelings as their cards became a picture inside someone else's app.