Possible interpretations:
* It could be a specific acronym used within a particular field or organization. To know what QUID means, you'd need more context. For example, if you saw it used in a scientific paper, a company document, or a specific online forum, it might be a term used within that context.
* It could be a misspelling or a random string of letters.
If you provide more information about where you saw "QUID," it might be possible to figure out what it stands for.