Apioforms are a somewhat heterogeneous group of apionic entities that occur within three-dimensional space at a large enough scale to be observed macroscopically (typically hundreds of metres or greater) and persistently. They differ from tesselating phenomena, such as apionic quasicrystals, by a lack of periodicity and repeating structure. The word "apioform" is derived from the words "apion" and "form", which together literally mean "apionic form" or "form of apions", referring to the apionic nature of most such structures. While all known apioforms are apionic, it is not certain that no non-apionic apioforms exist, although they would certainly be rare, because most known non-apionic structures are not large or complex enough to be considered apioforms.

Apioforms are distinct from smaller apionic structures such as apionic catalysts, which are apionic structures that can be created by human action to effect changes on apions in apionic fields, usually by rapid fluctuations or other forms of instability. Apioforms, in contrast, can only be reliably created by apionic megastabilization processes, which are not known to have ever occurred naturally or due to the influence of humans, or through rare, extremely high-energy processes such as apionic anabaptization. In some rare cases, they can be created by large-scale application of apionic catalysts, or certain materials with a negative apionic ratio. Very rarely, they can be created in response to large-scale human actions which usually involve the creation or elimination of large amounts of catalysts. Because of these facts, apioforms are a good example of an extremely low-probability but extremely high-consequence occurrence, similar to vacuum decay and other such phenomena.

Apioforms are usually not stable, although stable apioforms can be created and preserved with enough energy. Most apioforms tend to last anywhere from a few years to millions of years. Unstable apioforms can usually be destroyed by human intervention by means of the injection of apionic catalysts, or the destabilization of the apioform with other apionic structures. Because of the relative simplicity of most apioforms, they can usually be identified as apioforms quite easily. However, the identification of certain complex apioforms as such can be quite difficult, especially when they do not appear to be apionic in nature. Due to their relative rarity and the difficulty of identifying them, apioforms are not well understood and have not been studied much by humans. The existence of apioforms was only proven conclusively in the late 1800s, and it was not until the 1950s that their apionic nature was fully understood. The study of apioforms is still in its infancy, and most of the current knowledge about apioforms comes from theoretical physics and observation of known apioforms.