This event was intended to get us started and more than delivered.

We had a lot of fun and the one interesting fun fact we discussed (amongst many) was the etymology of the word Pound and its symbols.

We used AI to query and verify our discussion post event – result pasted below.

The same word “pound” in both money and weight comes from the same ancient root—because money originally literally was a weight of silver.

1) Origin of pound as a weight

The weight sense comes from the Latin phrase libra pondo, meaning “a pound by weight.”
• libra = scales / balance / a Roman pound
• pondo = by weight

Over time, English kept:
• the word “pound” from pondo
• the abbreviation “lb” from libra

That’s why:
• 1 pound = 1 lb
• 10 pounds = 10 lb or 10 lbs
• scientists often prefer lb for both singular and plural

So the spelling mismatch exists because the full word and the abbreviation come from two different parts of the same Latin phrase.

2) Origin of pound as money

The money sense is directly linked to the weight sense.

In medieval England, one pound (£1) originally meant the value of one pound weight of silver.

So historically:

£1 = one pound (weight) of silver

That is why the British currency is still called the pound.

So both meanings share the same idea:

measured weight → measured silver → monetary value

3) Why the symbols are different

There are two different symbols people often confuse:

lb

This is the weight abbreviation
• comes from libra
• used for mass/weight
• examples:
• 5 lb
• 150 lb

£

This is the currency symbol
• also comes from libra
• it is basically a decorated letter L
• the line through it was a medieval scribal mark showing abbreviation

So:
• £20 = twenty pounds sterling
• lb = pounds in weight

Same Latin origin, different modern use.

4) The simplest way to remember it

A nice memory trick:
• pound (word) → from pondo
• lb (weight) → from libra
• £ (money) → stylized L from libra

That’s why English ended up with the odd but logical trio: pound, lb, and £ all share Roman roots.

It’s actually one of the best examples of how language preserves ancient accounting systems.

The evolution of the Sign

Medieval manuscripts used a “blackletter” L with a tilde or stroke to show it was an abbreviation.
Common Use: By 1661, the stylized £ sign appeared on checks, and by 1694, when the Bank of England was founded, it was standard.
Bank of England +5

Important Distinction:
Double vs. Single Crossbar: Both single (£) and double-crossbar (₤) versions existed historically, though the single bar became standard.