"Grue" has a surprising variety of meanings:

Obsolete/dialiectical English: to shudder with fear, or a shudder (related to "gruesome")

Computer games: in Zork, a monster that eats adventurers in the dark [0]

Linguistics: an English translation for words that cover the entire green-blue part of the spectrum (in languages that don't distinguish blue from green) [1]

Philosophy: a color name that is equivalent to green until a specific future time, at which point it becomes equivalent to blue (used to raise questions about how to validly extrapolate into the future) [2]

[0]: https://zork.fandom.com/wiki/Grue

[1]: https://en.wikipedia.org/wiki/Blue–green_distinction_in_lang...

[2]: https://en.wikipedia.org/wiki/New_riddle_of_induction#Grue_a...