Does anyone know why pounds is abbreviated lbs instead of pds or pns?

Answer 1

The connection with Latin "libra" meaning "scales" is correct. But WHY (you may ask) use a Latin abbreviation instead of an English one?

First note that "lb(s)" is one of MANY Latin abbreviations used in English.

This is rooted in the important role Latin played for centuries as THE universal academic language in Europe. Eventually officials and scholars begn to write in their native languages. But "many Latin abbreviations continued to be used due to their precise simplicity and also Latin's status as a learned language."

http://en.wikipedia.org/wiki/List_of_Latin_abbreviations
(Also includes a list of many of the abbreviations that are still used.)

--------
A related (?) observation on usage --

In general, when you see the Latin abbreviation, do NOT speak the Latin expression. Use its English equivalent. (Most people do that for abbreviations where they are not sure exactly what the Latin is, but insist on saying "et cetera" rather than simply "and so forth" or even "id est" instead of just "that is".)

Answer 2

We get the word 'pound' and it's abbreviation of 'lb' from two different sources. First, 'lb': The origin is in the Latin word libra, which means both balance scales (hence the symbol for the astrological sign Libra, which was named after a constellation that was thought to resemble scales) And as for 'pound': a pound weight, for which the full expression was libra pondo, the second word being the origin of our pound.

Answer 3

Lbs. comes from the latin word "libra" which means "scales" or "balances". Libra was a Roman unit of weight similar to a pound.