Meaning of thumbing the nose / biting the thumb

Factual Questions
1

I’ve seen references to the latter in Shakespeare and sme other literature, and the former in more recent texts. What significances do these insults hold?

2

I’ve heard it basically means “fuck you”. Could be wrong, but that’s what I’m putting my money on.

3

Ah…are you referring to Romeo and Juliet?:
“Do you bite your thumb at me, sir?”
“I do bite my thumb at you.” (or something like that, anyway).

Basically, I’ve been led to understand that this about the same as flicking someone off nowadays.

4

I think it is equivalent to the middle finger .

5

I think it’s:

-Do you bite your thumb at me, sir?
-I bite my thumb, but not at you.

A quick check at BookRags gives me:

6

I don’t know about biting the thumb, but I always thought thumbing the nose (touching the tip of your nose with your thumb, palm open and fingers up) meant “kiss my ass.”

7

Fr. DeBoiser, my HS English teacher who knew everything about English lit, said the meaning was unknown but it was generally considered to be equivalent to the middle finger.