Where the words come from
The definition of money, barter and the double coincidence of wants, the four functions of money, and commodity and fiat money — Principles of Economics 2e, OpenStax, licensed CC BY 4.0. https://openstax.org/books/principles-economics-2e/pages/27-1-defining-money-by-its-functions. Changes: the Bierce quotation and the silver-certificate history dropped; "dollar bills" to notes; the US legal-tender wording generalised; the card definitions trimmed from 2e's wording of each function ("acts as an intermediary between the buyer and the seller", "it will still hold its value the next day, or the next year", "the ruler by which we measure values", "buy goods and services today and pay in the future"); the plumber examples, the wealth definition and the money-and-wealth contrast are ours; British spelling.
Liquidity, and why a credit card is a loan rather than money — Principles of Economics 2e, OpenStax, licensed CC BY 4.0. https://openstax.org/books/principles-economics-2e/pages/27-2-measuring-money-currency-m1-and-m2. Changes: the liquidity definition shortened; "checking account" to current account; the house example is ours.
The question and the page layout are our own.