[From Insufficient Balance blog, by Paul Leishman, 7 May 2012]
If you spin the virtual globe on GSMA’s Deployment Tracker and take note of the names of mobile money services around the world, you may find yourself with a sense of dejà vu. There are no fewer than six countries where the name of a mobile money service includes the word “pesa” or some variant of it. Here’s the list:
What’s remarkable is that these services are scattered across East Africa, West Africa, the Pacific Ocean, Asia, and Central America. How can the word “pesa”, or some variant of it, possibly mean the same thing in all of these places? To answer this question I consulted Ignacio Mas, master of global languages. His answer is below, and we invite any linguists to provide their grand theories in the comments.
“There seem to be two roots for this collection of seemingly-related words. One is from the Latin "pensum" for weight, from which you have the modern Spanish word "peso." Developing standard weights was of course essential in commerce. "Pesos" were the pieces of metal that you'd put on the other tray in the scale to balance out whatever it was that you were weighing. It's easy to see how you'd go from a "peso" representing a standard measure of weight to representing a standard measure of value. By the way, naming currencies after standard measures of weight seems to be a well trodden etymological path: think of the British "pound."
Interestingly, we never had the "peso" as currency in Spain, even though the term became a unit of currency throughout Latin America and the Philippines (too bad you couldn't add "Smart Pesos" or "G-peso" to your list) in Spanish colonial times. But in fairly modern times we did have the "peseta" in the metropolis, before we had the euro (which I hope we will still have when your blog post gets published). It is thought that the "peseta" does not in fact derive from the Spanish word "peso" but rather is a diminutive of the Catalan word "peça" (pronounced "pesa") for "piece." You'd quote something as costing a few little pieces...
The second root I find is from the Sanskrit word "pȧd," meaning "one fourth" -- kind of like the US "quarter," I suppose. This led to the Hindi word "Paisa" and then traveled across the Indian Ocean to East Africa and seeded the Swahili word "Pesa."
I have not been able to uncover a link between the (presumably older) Sanskrit "pȧd," and the Latin "pesum." I’d assumed the link was Arabic, and that Arab traders popularized the eastern term wherever they went, but that doesn’t seem to be the case. There appears to be much more phonetic resemblance in present-day derivations of these words than between the root words themselves, so it could be coincidence.”