Ok, I had to go to dictionary.com to look it up. It is an adjective meaning "deadly", and yes, it was an invented word by Lewis Carroll. I am taking some degree of satisfaction from the fact that I already knew that (insert smug smile) and can still quote a large portion of "The Jabberwocky", thus embarassing my children.
On a related note, I was surprised the other day when I quoted a portion of "If", by Rudyard Kipling, and John was not familiar with it. I had to memorize it in 10th grade English - I guess I assumed it was a pretty standard poem for high school. It amazes me sometimes that we've been married almost 19 years (August) and there are still things we don't know about each other.