A book of maps bound together — many territories held in one hand. An atlas does not own the lands it shows; it lets any traveler see how they join.
Greek Atlas, the Titan condemned to bear the sky on his shoulders, read since antiquity as from tlenai (to bear, to suffer) with a negating a- prefix, though the derivation is not fully secure; the bound-book-of-maps sense arrives in 1595, from a collection whose title page pictured Atlas holding the globe.
A bound set of maps held in one hand, showing how many territories join without owning any of them.