Outgassing

Part of speech: noun, verb

Definitions

1. The process involving the emission of gas that was previously contained within a solid or liquid due to heat application or pressure reduction
2. A phenomenon where substances expel gases trapped within them, typically in response to thermal or vacuum conditions
3. The action of releasing trapped gases from solids or liquids occurs when subjected to heat or pressure changes

Etymology: "Outgassing" is built from "out" and "gas," and its history is essentially that of its two parts. "Out" descends from a Proto-Germanic form and has been in English since Old English as "ūt," while "gas" is a much newer word: it was coined in the 1600s by the Flemish chemist Jan Baptist van Helmont, who took it from the Greek "khaos," meaning chaos or the empty void, and it passed into English through Dutch. The compound itself is plain. "Outgas" means to release gas, most often gas that was held or absorbed in a solid or liquid, and "outgassing" is the process of that release. The verb makes sense of the prefix: "out" signals escape from inside something, the same way "outflow" or "outburst" do.