Vacuum technology

Fifteenth in the list is a desgaseificação, a single noun standing where English keeps two that face in opposite directions. « Outgassing » is what a material does of its own accord: the steel wall of a chamber lets go, hour after hour, of the water and the hydrogen it took in while it stood in the workshop, and nobody asked it to. « Degassing » is what somebody does to something else: a resin, an oil or a solvent is held under vacuum until the gas dissolved in it comes out, and the agent is a person with a pump. The grammar carries the difference — one is intransitive and unwilled, the other transitive and deliberate — and a desgaseificação covers both without a flicker. The consequence shows up twice in this list. A desgaseificação das paredes is « outgassing » and never « degassing », because the wall is the one doing it, and the entry after it, o aquecimento sob vácuo, is the counter-measure, which English gives a third word again: « bakeout ». Write « degassing » of a chamber and a reader starts looking for the operator.