“Pound”‘s Latin origins are also the reason the symbol for the British currency, pounds, is an L—L for libra! The currency shares its name with a unit of weight because a British pound originally held the same worth as one lb of silver. We actually owe much of our modern alphabet to the ancient Romans; here’s why.

Lb is an abbreviation of the Latin word libra. The primary meaning of libra was balance or scales (as in the astrological sign), but it also stood for the ancient Roman unit of measure libra pondo, meaning "a pound by weight." We got the word "pound" in English from the pondo part of the libra pondo but our abbreviation comes from the libra.

The word "pound" is short for "pound weight," which was libra pondo in Latin. The libra part of the phrase meant both weight or balance scales. The Latin usage was shortened to libra, which naturally was abbreviated "lb."