Multum in parvo
Multum in parvo (pronounced /ˌmʊlt
ʊmɪnˈpɑrvoʊ/) is the phenomenon in which the interior of an object or part of space is larger than the volume in space it occupies or displaces. This is a common type of enchantment for talismans, used to create magical bags and chests with many times their apparent capacity. On a larger scale, it can also be used to make rooms or entire buildings much larger than their exterior dimensions would seem to allow. Multum in parvo is often called "mip" (pronounced /mɪp/) for short, this form also being used as a verb applying to the process of producing this phenomenon, and, rarely, an adjective to apply to objects that exhibit it. A chest that is affected my multum in parvo, for instance, could be said to be mipped, or, infrequently, could be called a mip chest.
There are two basic ways by which multum in parvo can be effected, though for all practical purposes the end result is almost identical. For one, they can work through the curvature of space itself; the space inside the mip volume is sharply expanded without affecting its boundary. The effect is similar to blowing a bubble in a flat sheet of rubber, except in a higher dimension. Alternately, the density of space itself can be changed, so that the space inside the mip volume isn't actually curved but nevertheless has a different metric applying to it. Which form of multum in parvo is used depends on the arcanum, and perhaps on the particular spell or effect involved; or, if the mip is brought about technologically, by the details of how it is brought about. There is a third way to produce a similar effect—by arranging for the boundaries of the volume to translocate objects that pass through it to a different location, preserving an illusion of physical continuity while still allowing the appearance of an anomalous interior size, but this isn't considered true multum in parvo, though it's still sometimes called that.
Aside from its use in talismans and technology, multum in parvo may sometimes arise naturally. In Xi, for instance, gravitational effects distort space enough to produce the effect—black holes technically involve multum in parvo, but in a very dangerous and inutile way. Moreover, especially on magical worlds, some species of creatures may develop multum in parvo abilities, allowing them to build large lairs in small areas, or to swallow prey that greatly exceeds their own size.
Multum in parvo does not inherently involve any change in mass or weight; without further enchantment, a magic bag holding a thousand bars of gold may still be small enough to fit in a pocket, but would still weigh as much as a thousand bars of gold. However, it is possible to attach to the mip other enchantments or technological manipulations to reduce the weight as well as the volume, making the objects inside effectively weigh only a fraction of what they would outside the container, or perhaps weigh nothing at all. In fact, this is so common that on many worlds multum in parvo is tacitly assumed to include this weight effect unless stated otherwise. When the distinction must be made, however, the mip effect is called "pondic" (/ˈpɔːndɪk/) if it also affects the weight, and "non-pondic" otherwise. Sometimes pondic multum in parvo is abbreviated "pip", and non-pondic "nip" (so a container would be "pipped" or "nipped" according to which form applies to it), but these words are still considered nonstandard and somewhat jocular.