It probably doesn't need to be in a dictionary because it's just a compound of two words, rarely used as a singular word until recently, except in the specialist field of distilleries. It could just as easily be written as "wash back" or "back wash" or "backwash" or "back flush" or "backflush" (backflush is usually used in a different context, but technically has the same literal meaning). You can use these terms in any context you wish - it might not be common but because they're just combinations of 2 simple words, it should still be understood.

Yes, the term washback can be used in contexts beyond testing, although it is most commonly associated with education. Washback refers to the impact or influence one thing has on another, particularly when one process affects subsequent processes or behaviors. In a broader sense, you can use washback to describe unintended or secondary effects in various areas, even if it’s less common in everyday language. For example: Political washback: The ripple effect that political decisions have on public opinion, policy, or international relations. Environmental washback: The indirect impact of environmental policies or practices, such as when industrial regulations affect wildlife or community health. Economic washback: When a particular economic policy or event influences consumer behavior or business practices in a related area. Washback is often discussed in research or technical contexts, where people are examining the side effects or downstream effects of a primary action. It’s a useful term when you're looking to describe secondary impacts that weren't initially anticipated but play a significant role in shaping outcomes or behavior.

Yes, “washback” can be used in broader contexts, though it’s more commonly found in educational and assessment-related discussions. The term generally refers to any consequence or repercussion of a particular action or decision. For example: * Economic washback: The effects of an economic policy on businesses or consumers. * Political washback: The impact of a government decision on public opinion or international relations. While it’s less common in everyday language, “washback” describes the ripple effects that follow a specific event or choice—similar to "fallout" or "repercussions."