I am wondering if this a word or phrase for a problem that is encountered the first time? So, a problem or failure in a system that is encountered for the first time. I thought about asking this question on computer or programming or engineering stack exchange, because I really feel like those fields would have a word for this. Is there already a word for this?

So, it's kind of the opposite of this question, because they are looking for the thing that solves a problem for the first time, and I am looking for what a first, unique problem or failure or glitch is called. This is the only question I can find that is similar to this question.

As an example, I would use the Tacoma Narrows Bridge. I watched something on Modern Marvels about it, how the winds in the Narrows was too much and caused it to collapse. And the way Modern Marvels made it out, was that it was unknown to engineers that wind would have such an effect on such a long span of bridge, because it was the first time encountering the combination of winds and length. Now, whether that's true or not is irrelevant. If it's wrong, feel free to comment, but for the sake of the question, just pretend it's true. So, is there a term for a problem that is encountered for the first time?

  • Are you talking about flying pigs, or are you talking about black swans? I ask because those two do not represent the same class of out-of-context event.
    – tchrist
    Commented Sep 28, 2022 at 23:09
  • 1
    'Novel problem' is the two-word term (if that's any help) that springs to mind This article by Wendy Inn at LinkedIn shows the usage. CD and M-W add the 'hitherto unidentified / not like anything seen before' broadening to the 'new, original' sense for the adjective 'novel'. Commented Sep 29, 2022 at 11:34
  • @tchrist, I don't understand the question. Commented Sep 29, 2022 at 18:31
  • @EdwinAshworth that does help. These terms don't roll of the tongue, well enough. I think I am going to have create a word. It's for a story. Thanks for the references. Commented Sep 29, 2022 at 18:33

2 Answers 2


In one specicific sub-area related to the declared background of the Poster, the term

Zero-day exploit

relates to a “problem that is encountered the first time”.

The Wikipedia entry for Zero Day, shorn of some of what I regard as subjective opinionating includes:

A zero-day (also known as a 0-day) is a computer-software vulnerability previously unknown… An exploit taking advantage of a zero-day is called a zero-day exploit, or zero-day attack.

The key point of this definition (my bold emphasis) is that until it is exploited, the vulnerability is unknown, i.e. when it eventually is exploited it is being encountered for the first time.


All the words here have nearly the same meaning of "unanticipated problem". I am posting them here as it would be too big for comments and also because I liked the word "curveball" too much.

Poser (Wiktionary) A particularly difficult question or puzzle.

Jolt (Wiktionary) To push or shake abruptly and roughly. (transitive) To shock (someone) into taking action or being alert

Curveball (Cambridge)

  1. in the sport of baseball, a throw in which the ball curves as it moves towards the player with the bat

  2. something such as a question or event that is surprising or unexpected, and therefore difficult to deal with:

  • I hate the word curveball. It is not British English. Although I did watch baseball during my three years living in Chicago, I can assure you it has a similar effect on many of my compatriots to (my favourite cricket term?) googly.
    – David
    Commented Mar 10, 2023 at 16:33

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