Nilation is a term coined by the YouTube star NileRed in one of his videos^[1], in reference to a physical process in which a solid material converts directly into a gas. In conventional chemistry and physics, this process is known as sublimation, however, what he noted was that there are actually in effect two different direct solid-to-gas transition processes: one of these which has a definite phase change temperature that the material must be heated to and at which point it undergoes a behavior similar to boiling, in that its temperature stops rising and all further heat input goes into gasifying the material until it has been fully so, and the other, in which the material is well below this hard phase change temperature, yet converts more slowly. For the liquid state, the analogous process is called evaporation, as distinguished from boiling, but there is no pair of distinctive terms for these two processes. His suggestion was to call this latter process nilation, while the former, boiling-like process would continue to be called sublimation.

A commenter^[2] on the video in which he introduced this term affirmed the validity of the idea and then suggested a better name for the process might instead be effugation (from the Latin word for "escape", or more literally, "to take flight" - c.f. fugitive), as more consistent with the Latinate derivations of the other terms (and perhaps also less egocentric to the video creator).