Apartments

According to the Wallace Stevens concordance, the word “apartments” appears only once within the poetry. In "Notes Toward a Supreme Fiction " (ii.1), Stevens writes:
It is the celestial ennui of apartments
That sends us back to the first idea, the quick
Of this invention; and yet so poisonous
Are the ravishments of truth, so fatal to
The truth itself, the first idea becomes
The hermit in a poet’s metaphors,
Who comes and goes and comes and goes all day.
The “this” of “this invention” refers to the invented world—i.e., the world invented by the imagination, the “inconceivable idea of the sun” (i.3). The sense of the lines seems to be that we are driven to the world of imagination by the sheer dullness of a Heaven that never changes; yet acknowledging that our world is “invented” contains such hazards that only the poets may speak of it safely. Even then, they must cloak this truth in metaphors.
==Etymology==
Yet why the celestial ennui of apartments, rather than just “celestial ennui?” We are familiar with the English meaning of the term as a rentable room in a building. It derives, however, from the French appartement and the Italian appartamento, words meaning “to separate” or “to divide.” 
By indicating that celestial ennui is a product of separation or division, Stevens could be expressing his disapproval of anything that cuts one off from the earthly world (both real and imagined).
Frank Lentricchia offers a different interpretation. He suggests that Stevens was a poet with the modern-day equivalent to an aristocratic sensibility: he shared the avant-gardist loathing of mass culture. "Apartments," on Lentricchia's view, indicate everything that is mass produced, things made that are exactly like the other things made -- or, in Lentricchia's phrase, exists in "repetition" of one another.
::: Living in a world of repetitions (whether in groceries, popular genre fiction, or apartments: "the ennui of apartments,"). . .  had the effect of withering Stevens' aesthetic sensibility, which inclined him to want precisely that rare thing which his commodity culture by intention does not produce. (Modernist Quartet, 141)
: Lentricchia, Frank. Modernist Quartet. New York: U of Cambridge P, 1994.