The Board of Trade Unit
The reason your electricity bill still says "units".
Origin
Established under the Electric Lighting Acts, which made the Board of Trade the authority for electrical standards as public supply spread from the 1880s.
The catch
The Board of Trade Unit is simply the kilowatt-hour. The name vanished from law decades ago, but British electricity bills still describe consumption in units, and a good many customers have no idea they are quoting a Victorian government department.
The Board of Trade appointed electrical standards inspectors and maintained reference instruments, because a nascent industry selling an invisible product needed a referee. That regulatory function passed through several bodies and now sits with Ofgem and the National Physical Laboratory, but the vocabulary survived the institutions. It is a small monument to Victorian administration on every quarterly bill.