Derrida used "χώρα" to name a radical otherness that "gives place" for being. El-Bizri built on this by more narrowly taking "khôra" to name the radical happening of an ontological difference between being and beings. El-Bizri's reflections on ""khôra"" are taken as a basis for tackling the meditations on "dwelling" and on "being and space" in Heidegger's thought and the critical conceptions of space and place as they evolved in architectural theory (and its strands in phenomenological thinking), and in history of philosophy and science, with a focus on geometry and optics. This also describes El-Bizri's take on "econtology" as an extension of Heidegger's consideration of the question of being ("Seinsfrage") by way of the fourfold ("Das Geviert") of earth-sky-mortals-divinities ("Erde und Himmel, Sterblichen und Göttlichen"); and as also impacted by his own meditations on Derrida's take on "χώρα". Ecology is hence co-entangled with ontology, whereby the worldly existential analytics are grounded in earthiness, and environmentalism is orientated by ontological thinking