Here is a possible explanation of the meaning of the poem:

Big Monster

An Abstraction of a Translation of Jabberwocky

It was summer
everything was in bloom
fruit got ripe
farmers did all right

"Watch the big monster, boy
It can kill you
Watch the hawk
and the big cat"

He armed himself
looked all over for the big monster
stopped in a strange place
rested and thought

And when he dropped his guard
the big monster, looking scary,
charged him through trees
making lots of noise

With accuracy and speed
he used his sword
killed the beast, cut off its head
and went home

"Did you get him?
You make me proud, son!
This is great! Yow!"
he exclaimed

It was summer
everything was in bloom
fruit got ripe
farmers did all right

I like this in particular because it demonstrates the fallacy of translating nonsense poems. Jabberwocky has been translated into several languages (see Jabberwocky Translations), but can a poem which has little or no explicit meaning be translated? When it is translated would it still feel the same to a native speaker of another language? The poem above for example has the same explicit meaning as Jabberwocky itself but certainly doesn't conjure up the same images, so is it a translation?

There is an in-depth discussion of this very idea in Douglas Hofstadter's book: Gödel, Escher, Bach: An Eternal Golden Braid, where he discusses the very nature of meaning.