Weights and Measures – the Imperial Pound, Ounce, lb and oz

By , September 28, 2009 1:47 am

Introduction

Over time, there have been many different “pounds” used in England, from the 12th century onwards. The only one in common parlance today is the Imperial pound, which is made up of 16 ounces, and 14 pounds make up a stone.

English people almost always use imperial measures for people, although the metric system has also been taught in schools for decades. For example, I’m 32 years old, and I know I’m 5 ft 7 and stone and pounds, I’m not entirely sure what my metric numbers are, though.

So why “lb” for “pound”, and “oz” from “ounce”?

Writing or noting a weight down, abbreviations come into play. A pound and a half of sugar, for example, would be written as 1.5lb, or 1lb 8oz. The abbreviations, used in other countries which maintain stones, pounds and ounces, seem a little obscure. How does one get “lb” from “pound”, or “oz” from “ounce”, exactly?

The answer, not surprisingly as we’re discussing English history, is both illogical and very old indeed.

The word “pound” comes from the Latin word pondus, meaning “weight”. “Ounce” comes from the Latin uncia, meaning a twelfth, the same word being the root of the English “inch”, too.

At one time, there were 12 ounces to the pound, rather than the 16 ounces we have today. 12 ounces to the pound survived in the troy ounce and troy pound, for weighing precious metals, but by the mid-13th century, there were 16 normal ounces to the standard pound.

The abbreviations, lb and oz, also have foreigh origins – but different ones, bizarrely, from the main words. “lb” comes from the Roman pound, called libra – also the origin of the French word libre (pound) which in modern French has come to mean half a kilo, or 500g.

“Oz” comes from the medieval Italian onza, meaning “ounce”.  Obviously……

The complete list of weights in the pound-and-ounce system

16 drams = 1 ounce
16 ounces = 1 pound
7 pounds = 1 clove
14 pounds = 1 stone
28 pounds = 1 tod
112 pounds = 1 hundredweight
364 pounds = 1 sack
2240 pounds = 1 ton
2 stones = 1 quarter
4 quarters = 1 hundredweight
20 hundredweight = 1 ton





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