In a pique of pedantry, I looked up definitions for those things law firms send in for payment:
Bill: “a statement, usually itemized, of charges for goods or services; invoice”; dictionary two says, “a statement of money owed for goods or services supplied.”
Invoice: “an itemized list of goods shipped to a buyer, or of services rendered, stating quantities, prices, fees, shipping charges, etc, often with a request for payment”; dictionary two: “a detailed list of goods sold or services provided, together with the charges or terms.”
Statement: “a listing of charges for goods or services; bill”; dictionary two: an abstract of an account, as one rendered to show the balance due.”
Emerging from these circular definitions, having nevertheless achieved karmic enlightenment, I pronounce that law firms should send invoices. An invoice contains more information – certainly than the bare-bones, dunning notice of a statement, and even more than the “services rendered” brevity that can be a bill.
Now, even without recourse to etymology, don’t we all feel precise and relieved. Let’s get on with approving whatever we call them.