John Baez wrote: (in newsgroup sci.math.research - 2010-06-29   15:00)

What's the origin of the mathematical term "plethysm"?  I hear that someone suggested this term to Littlewood, but
who?  And why?  And what's the etymology?


Etymology of "plethysm" ("πληθυσμός"):
see http://en.wiktionary.org/wiki/%CF%80%CE%BB%CE%B7%CE%B8%CF%85%CF%83%CE%BC%CF%8C%CF%82

(the "%CF (...) %82" string represents the word "plethysmos" in the Greek spelling in Unicode.)

Meaning of modern Greek "plethysm" ("πληθυσμός"):
see http://lexicon.pathfinder.gr/ ,
online lexicon for English to modern Greek and vice versa;
entering "πληθυσμός" yields the URL
http://lexicon.pathfinder.gr/?lookup=%F0%EB%E7%E8%F5%F3%EC%FC%F2&go=%CC%E5%F4%DC%F6%F1%E1%F3%E7
and gives the translation "population". This meaning is already present in ancient Greek.

My extended school dictionary
(F. Muller: Grieksch Woordenboek, 2e druk, J.B.Wolters, 1926)
gives among others
"plethos" ("πλήθος") = big number of ..., throng;
"plethyno" ("πληθύνω") = to fill, to increase, to be full of ...
"plethysmos" ("πληθυσμός") does not appear in this dictionary.

Enjoy - ciao: Johan E. Mebius