Quarter (qr)

A quarter of a hundredweight, being 28 pounds or two stone, and a working tier of the coal and produce trades.

The quarter sits between the stone and the hundredweight and takes its name from the larger unit, not the smaller: it is a quarter of 112 pounds rather than any multiple of fourteen, though it happens to be both. That the hundredweight divides cleanly into four quarters, eight stone and 112 pounds is precisely why it was fixed at 112 rather than 100. The word does duty elsewhere in British measurement and rarely means the same thing twice: a quarter of grain is eight bushels, a quarter of cloth is nine inches, and a quarter of the year is thirteen weeks. Only context tells you which is meant, and old trade documents assume you already know.