TIL the unit suffix for pounds (weight), lb, comes from the Roman-latin word Libra (for the balance). This is also where the (proto-)currency units livre, lira, and the pound sterling sign comes from, with £ being a German blackletter L with a cross through it
Strangely, #, what we'd call hash, sharp, or the pound-button on a phone, turns out to originally be a ligature for lb, which is why it's called the pound sign in phone parlance. Apparently it was common in the US to use this symbol in place of lbs.
Ligatures are weird man.
Bonus content: the ounce comes from the Latin word uncia, which literally means one unit, (in this case one twelfth-division of a pound, since everything was duodecimal back then). It also meant that an uncia could refer to an inch (a twelfth of a foot), or a twelfth of a jugerum (a unit of area).
If you start looking too deep into the history of division and multiplication of units your brain will leak out your ears realizing people thought it was a good idea to mix divisions of 12 (Troy), divisions of 16 (Avoirdupois), and multiples of 14 (stone?????). And this is just weight. Going back to currency gets even wilder.
The duodecimal system also sort of explains why words like "quincunx" are popular in Astrology, which is literally just 5 (quinc) out of 12 (unx). The only other irreducible fractions are 7 (septunx) and 11 (deunx, or rather one-from-unx, hence the de- prefix), which means they get sexy names too.