Perhaps you're thinking of another word from the poem? Some of the most famous nonsense words from "Jabberwocky" include:
* Jabberwocky: The fearsome creature that the hero must slay.
* Jubjub bird: A creature described as "frabjous" (delightful).
* Mimsy: A word meaning "flimsy and foolish."
* Tumtum tree: A tree that "grows in the valley of the Tumtum."
If you have another word in mind, let me know and I'll try to help!