The Ace of Disks represents the root of the powers of Earth, which Crowley did not view as passive or inert, but active, in motion. To highlight this animated quality of earth, the Thoth deck invokes a whirring disk, rather than a coin or a pentacle. Crowley writes:  Thus, in particular, the old conception of the Earth as a passive, immobile, even dead, even “evil” element, had to go. … Nor are the Disks any more to be considered as Coins; the Disk is a whirling emblem. Naturally so; since it is now known that every Star, every true Planet, is a whirling sphere. The Atom, again, is no more the hard, intractable, dead Particle of Dalton, but a system of whirling forces, comparable to the Solar hierarchy itself.

The background of this card is lush green stippled with gold: the colour of sun leaking through fir branches, or a beam of light rinsing the face of an emerald. We see four sets of wings, of angels or peacocks. (The Book of Thoth does reference Isis with this card, and a peacock is one symbol for the Egyptian goddess.)

In the centre of the card, the whirling disk itself is printed with Crowley’s seal: ΤΟ ΜΕΓΑ ΘΗΡΙΟΝ. It means “the Great Beast,” a reference to the Beast prophesied in Revelation. The letters add up to 666 using isopsephy, and 666 is inscribed in the centre of the disk inside the tiny triad of circles. Here we land on a striking archetypal point: the earth element as corrupt or corruptible. Our bodies and the material realm as somehow embarrassing or wicked. The Devil in this deck is linked to the sign of Capricorn, for instance. (The goat.)  I can’t help but wonder if the subtle maligning of the material realm in western culture has contributed, even tangentially, to how little we respect our planet.

This card represents the purest form of the Earth element: raw material; money; exchange; prosperity; abundance; pragmatism; security; stability; the ability to make shit real, or manifest. Angeles Arrien suggests this card signifies inner and outer success. The four sets of wings indicate the four levels conscious development (mental, emotional, spiritual, physical), while the coins and crystals signify prosperity. To me, this card represents a seed. A new venture that involves the material realm, possibly money, but also any form of physical reality: seizing an idea or ideal (represented by air and fire) and crystallizing it into being. A sort of psychic 3-D printing. This card represents the triplicity of Earth in astrology: Taurus, Virgo, Capricorn. Earth as the stretching of tree roots, the weaving of words, the building of castles. Earth not as a static lump, but a whirling disk, the planet we’re living on.

References:

Book of Thoth by Aleister Crowley
The Tarot Handbook by Angeles Arrien
Esoteric Meanings