Well, the title clearly follows the title of [this](https://mathoverflow.net/questions/24090/what-is-so-spectral-about-spectra) question.


Why the objects so successfully defined by Grothendieck have been called "schemes"? In my opinion the original French word (*schéma*) doesn't help, by itself, to understand the motivations behind such a choice of nomenclature...



What's so "schematic" about schemes?
This is what Grothendieck says -- no difference with Andreas Blass, I just thought it might interest some as additional information -- in Récoltes et semailles (p. 31/32) [my emaphasize]:



> 
> La notion de schéma est la plus naturelle, la plus "évidente" imaginable, pour englober en une notion unique la série infinie de notions de "variété" (algébrique) qu’on maniait précédemment (une telle notion pour chaque nombre premier (39)...). De plus, *un seul et même "schéma"* (ou "variété" nouveau style) *donne naissance, pour chaque nombre premier p, à une "variété (algébrique) de caractéristique p" bien déterminée*. La collection de
>  ces différentes variétés des différentes caractéristiques peut alors être visualisée comme une sorte d’ "éventail (infini) de variétés" (une pour chaque caractéristique). Le "schéma" est cet éventail magique, qui relie entre eux, comme autant de "branches" différentes, ses "avatars" ou "incarnations" de toutes les caractéristiques possibles.
> 
> 
> 


My (poor) translation: 


The notion of scheme is the most natural, the most "obvious" imaginable, to encompass in one unique notion the infinite series of notions of (algebraic) "variety", which one used before (such a notion for each prime number(39)...) Moreover, *one and the same "scheme"* (or "variety" of a new form) *gives rise, for each prime number p, to a well-determined "(algebraic) variety of characteristic p."* The collection of these different varieties of different characteristics can thus be seen as a sort of "(infinite) fan of varieties" (one for each characteristic). The "scheme" is this magic fan, which ties together, as many different "branches", its "avatars" or "incarnations" of all the possible characteristics.


End of translation. [In particular the end might be a bit messed up, as éventail also has a botanic meaning and this might be the better one with the branches, but not sure.]


Footnote 39 merely mentions that this is to include primes at infinity.


P.S. In case somebody has suggestions for improvements of the translation, I'd appreciate them.


