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

By , September 28, 2009 1:47 am


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

9 Responses to “Weights and Measures – the Imperial Pound, Ounce, lb and oz”

  1. Brian says:

    It is quite handy knowing your metric measurement because when someone asks you your weight and you tell them, they still haven’t got a clue. Bring on the chips!!!

  2. Lauren says:

    See, now this is useful for women. Measuring my weight in stones is brilliant. Love the blog by the way.


  3. Very interesting that the English and American pound are both 16 ounces, but an American ton is only 2000 pounds, not 2240. Not that I buy many tons of anything (none, actually). But I do believe I’ll begin giving my weight in stone!

  4. sweetbearies says:

    I enjoyed the explanation of the origin of pounds. Never knew about this before!

  5. Sean says:

    Very interesting post. When I was younger my visiting relatives from Ireland would refer to their weight in stones. The old scale in our bathroom had both pounds and stones on it.

  6. Polprav says:

    Hello from Russia!
    Can I quote a post in your blog with the link to you?

  7. Interestingly, I obtained a Mayan brass weights set from Guatemala in 2008, that weighs exactly one pound and has six cups to it (for measures, also). It uses 12 ounces to the pound, using combinations of the cups/weights on a balance, or scale. Mayan history certainly preceeds Roman times, leading me to believe it to be far more ancient in its use. The question is: how did this weight set get from the old world to the new, or is its’ similarity just happenstance?

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