Beriah means creation. Cordovero connects the word to a verse in Numbers, "if the L-rd creates a creation," and explains its meaning: for thicker realities to exist, they must move away and separate from the hidden cause. They are not material, he specifies, but they are already outside the bounds of divinity, in the domain of separation and joining, of change and limit. He also links bara to a word in Joshua, "you shall clear it": to cut. The name of this world speaks of separation from the source.
The Zohar gives this world a name: kursaya, the Throne. Cordovero quotes the Raaya Mehemna: after the ten Sefirot, G-d made to serve them "a throne with four legs and six steps, that makes ten, and the whole is the throne." Beriah therefore has ten levels, like Atzilut, but it is their seat, not their substance. The Pardes reads Isaiah's verse this way: "all that is called by My name," called by My name, but not My name itself; "I created him," that is, separated.
Massekhet Atzilut, a small early treatise, describes what is found there: "I created him, this is the world of Beriah; there are the souls of the righteous and the treasuries of blessing and life, there is the Throne of glory," and palaces named will, love, merit and radiance.
The Ari links Beriah to Binah and to the first heh of the Name. He quotes the Zohar's formula, "the Mother nests in the Throne," which he reads with the partzufim: the light of Ima, the partzuf of Binah, descends through a screen and clothes itself in Beriah. Etz Chaim describes this passage as a seal: everything in Atzilut is imprinted in Beriah, soul for soul, body for body, garment for garment, palace for palace, and the Malkhut of Atzilut becomes the head of Beriah, its Atik. Cordovero quotes the same formula, but he refers it simply to the Sefirah Binah, source of the neshamah.
Finally the Tikkunei Zohar give this world a meaning in time. On Shabbat and festivals, the King wears "the garments of kingship, which are the ten Sefirot of Beriah"; on weekdays, He wears the ten classes of angels. Cordovero explains: on Shabbat, the world is conducted through Beriah, without passing through the angels. Keep this in mind as you dress for Shabbat: according to these texts, on that day the light reaches you from a higher world.
