ARAMyS is an acronym for "Alignment Reconstruction and Simulation for the ATLAS Myon Spectrometer". Aramis is one of the heroes of the novel "The Three Musketeers" (and various sequels) by the French author Alexandre Dumas. His (the hero's, not the author's) name is in fact spelled "Aramis", not "Aramys", but anyway "muon" is actually spelled "muon", not "myon" (which is correct only in German, although some people adhering to traditions claim it should rather be spelled "müon").
The purpose of the ARAMyS software is to reconstruct the alignment of objects, i.e. their positions and orientations in space, by using measurements from alignment sensors mounted on those objects. It was developed and tested in the environment of the ATLAS muon collaboration, but is not very ATLAS-specific and in principle applicable to any alignment problem.