A vec or bot that operates in conditions of extreme cold, well below the freezing point of water. Typically such m-life (machine-life) forms are found in the outer portion of a stellar system, well beyond the "frost line". Often, though not invariably, they have components that are volatiles at "standard" Terragen temperatures, or that have superconducting properties at low temperatures. Cryovecs are of course by definition sophont (that is to say intelligent and self aware) mechanical entities, while cryobots are merely sentient equivalents of biological animals, or are automatons with (often quite complex) programming. Cryovecs form a large proportion of many outsystem and Hider clades.
The Muuh often employ cryobots of their own design, some of which are built to designs many millions of years old. Some of the individual bots are apparently millions of years old as well, according to the Muuh. These devices are often very much damaged and eroded by micrometeorites and vacuum exposure, so the Muuh may be telling the truth for once. The Muuh do not use self-aware machines of any kind. Some suggest this is one factor in their long existence.