köken: From på (“on”) + krita (“chalk”), from an older practice of recording sales and debts on a chalkboard at pubs. Compare on the chalk. Attested since 1781.
Jag hade glömt plånboken hemma, men eftersom jag är stamkund och de litar på mig så lät de mig handla på krita
Literally, “on [a] notebook”, from the fact that when someone wants to buy something on credit, their name is jotted down in a notebook and is crossed out when the money is paid off.