English speakers who study chemistry may wonder why Pb is the symbol for the element lead, a word that has neither a p nor a b in it. Spanish speakers easily get half-way to an explanation because their word for lead is plomo. If we go back in time, we find that plomo evolved from the Latin word plumbum, from which chemists created the abbreviation Pb.
Returning to English, we see a borrowing of the Latin original in plumb, which is ‘a weight attached to the end of a string to make it hang vertically’; such a weight was presumably made out of lead, which is both heavy and easy to shape. Furthermore, because a weighted string hangs straight down*, English speakers took to using plumb as a synonym for ‘downright,’ as when saying someone is plumb crazy, meaning ‘downright crazy.’ And speaking of craziness, we know today that lead is poisonous, yet the word plomero/plumber tells us that water pipes used to be made of lead; modern historians attribute some occurrences of madness in past centuries to overdoses of lead from drinking water that had passed through lead pipes. In any case, I’d be crazy not to mention that the Spanish cognate for plumb is plomada.
The Old French phrase a plomb ‘perpendicularly’ led to the English noun aplomb, with figurative meanings ‘poise, assurance, self-confidence.’ The Spanish counterpart aplomo can have the literal sense ‘verticality’ but also the figurative meanings ‘gravity, serenity, circumspection.’
On the negative side, Spanish desplomar means ‘to cause something to lose its vertical position.’ With respect to a wall or building, the reflexive desplomarse is ‘to lean’ or even ‘to fall over, collapse.’ Also usually negative is English plummet ‘to fall at high speed, especially when out of control.’
© 2014 Steven Schwartzman
* Hang down, like fall down, is redundant, but I won’t get hung up on that now.