Was the term "module" in module over a ring originally chosen because of a relation to modular arithmetic?
Secondly, what is the etymology of the term "modular" in modular arithmetic? Does it have anything to do with "modular" in the sense of "consisting of multiple parts" (i.e. multiple modules), or something like that?
Jeff Miller's Earliest Known Uses of Some of the Words of Mathematics describes the origins of the word module as follows (boldface mine):
As for modular arithmetic, very little is said there about the etymology, it is only stated that
The site seems to be down at the moment, one can still read it from the web archive.