# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DcCWc5NRYs6
- **Gondola URL:** https://gondola.cc/posts/69054404-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/f0acfb2e57.jpg
- **Posted:** 2026-08-14T22:09:08.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

There is no letter L or B in the word pound. The abbreviation comes from a different language entirely.

Rome weighed goods in a unit called the libra pondo, literally a pound by weight. Libra was the unit. Pondo came from pondus, meaning weight. English speakers kept one half of that phrase and the abbreviation of the other. We say pound, from pondo. We write lb, from libra.

The libra was itself a balance, the twin-pan scales that underwrote Roman trade. One weighed roughly 329 grams and divided into twelve unciae. That twelfth-part word did remarkable work of its own:

- uncia became ounce, the twelfth of a Roman pound
- uncia also became inch, the twelfth of a foot
- libra became the Italian and Turkish lira
- libra became the zodiac sign Libra, still drawn as a set of scales
- libra became the pound sterling sign, an ornate capital L struck through with a bar

The bar is the tell. Medieval scribes crossed a letter to mark a contraction, and older printing shows the weight abbreviated as a barred lb, a stroke drawn straight through both ascenders. Apothecaries were still setting it in type well into the twentieth century.

The arithmetic drifted before the notation did. The Roman pound held twelve ounces. Merchants moving bulk cargo in medieval France worked to a heavier standard, avoir de pois, goods of weight, which handed English the avoirdupois pound of sixteen ounces. Precious metals stayed on the older reckoning as the troy pound of twelve troy ounces, named for the fairs at Troyes in Champagne. Two different pounds, two different ounce counts, one abbreviation serving both.

Which makes lbs a small fossil in the wrong grammar. Libra is a Latin noun that never needed an English plural welded to it, and nobody has declined it in earnest for two thousand years.

We threw away the word and kept its initials.

#stemantics #etymology #linguistics #historyofscience #wordorigins

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## Tags

etymology, wordorigins, historyofscience, stemantics, linguistics

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