The observable physical world of phenomena (effect), motion and 3-space. The physical body as opposed to the spirit, consciousness or mind occupying that body; Newtonian as opposed to non-newtonian.
"Each interchange between the invisible omnipresent universe where motion begins and ends, and the visible transient universe, which multiplies and divides the speed and power of motion, is a cycle. Pulsing cycles constitute the heart beat of this universe, which simulates Mind-Idea through pulsing cycles of two-way motion. Every pulsation of the life principle of multiplying motion creates divided electric male and female bodies, which seek rest in each other from the strains and tensions of their division into pairs of opposites." [Atomic Suicide, page 81-82]
"In materiality we find some advance faster, some grow stronger, some become weaklings. Until there is redemption through the acceptance of the law (or love of God, as manifested through the Channel or the Way), there can be little or no development in a material or spiritual plane. But all must pass under the rod, even as He - who entered into materiality." [Cayce (5749-3)]
"For, know, all things material have first their inception in the spiritual. Then they give or take form in the mental, finding expression in the material." [Cayce 2647-1]
"Water is as a womb where Father meets Mother Forces where Life is brought into materiality yet remains connected to Spirit or God forces. We were conceived and nurtured in womb water being as a remembrance to which we feel sympathetic (at home).
"...water combined of elements is the mother of creation." [Cayce (2533-8)]
1.14 - Materiality from Immateriality