The word krokopeplos comes from the Greek κροκοπεπλος. That word has two parts; the first, κρόκος (krokos) is the word for the flower whose English name is "crocus", a well as for the flavoring derived from its stamens, which is called "saffron" in English. By extension, it is also a name for the color of dye produced by saffron, a deep orangey yellow. The same word can also (because of the color) be used for the yolk of an egg, just like we call the other part of an egg the "white" in English.
The second part of the word krokopeplos is πεπλος (peplos), which is a type of dress or robe made from a single piece of woven fabric, similar to a toga or sari. In classical Greece, the peplos was most often worn by women, but there were also childrens' and men's versions. At its most basic, a peplos is wrapped around the body to form a tube whose bottom is near the ankles, and the top is well over the head. The top is then folded over to form a loose blouse, and fastened at the top of each shoulder, usually with pins. The more fabric is used, the more luxurious the peplos. A rich person (or a goddess) most often wore a very large volume of very thin, often sheer, fabric, which produces the many small pleats shown in classical art. The picture at the left, of a caryatid column from the Parthenon, shows such a luxury peplos. A poorer person's peplos used less fabric, of a thicker weight, more like a modern sundress. However, the word is sometimes used in a broader sense, to mean any kind of dress.
A krokopeplos is simply a yellow dress or robe. BUT, it is also far more than that. The epithet is used in ancient Greek for a variety of celestial goddesses. Homer uses it most often in describing Eos, the goddess of the dawn, the glow of whose sunny mantle warms the sky each morning. In the Orphic Hymns, it is applied to both Hekate and Melinoe (Persephone's daughter by rape, the goddess of nightmares). In Greek magical texts, it is applied most often to Hekate, Phoebe, and Selene, although also to a selection of other related goddesses, including Aphrodite. Infrequently, the epithet is also applied to male deities like Apollo and Helios.
In the Sisterhood of the Krokopeplos, we understand the krokopeplos to represent the glow of a celestial body (most often the moon) cloaked by clouds. While in the light of day, clouds obscure clarity, by night, they shine. Each tiny droplet become a lens, extending the illumination which would otherwise fail to penetrate the darkness. Clouds enrobe the moon in a golden halo, her krokopeplos.
Under the harsh light of day, certain kinds of truths are made clear; those with clear and firm boundaries, those unobfuscated by cloudy imprecision. The Sisterhood of the Krokopeplos embraces the empirical sciences, and the brilliant clarity about the world around us which they can provide. In fact, scientists and mathematicians are greatly over-represented among the Sisterhood, and the Sisterhood offers teaching in those matters. However, that is not our focus.
The Sisterhood of the Krokopeplos, rather, seeks to feel a void we observe in our society. We strive to teach those things some say are unteachable. In moonlight, clouds do not obscure light, they extend light where it might not otherwise reach. By "cloaking" the ineffable in parable, metaphor, and poetry, the krokopeplos extends the light of wisdom into the dark further than it might reach on its own. If you'd like to learn more about these two kinds of truth, you might like this essay about the Titans Phoebe & Koios, the parents of Asteria & Leto, and grandparents of Hekate, Artemis, and Apollo.