Much has been made of the name Mercutio in Romeo and Juliet, with many believing that Shakespeare named the character to link his personality to the word "mercurial," which for us today means "Volatile, sprightly, and ready-witted" (Oxford English Dictionary Second Edition on CD-ROM [v. 4.0]). And this would seem to be a great story and completely apt. Except for one thing:

THAT meaning of "mercurial" did not arise until over fifty years after the play was written.

Oh, yeah... that and the fact that Mercutio (as a named character) appeared in Shakespeare's sources for the play, including Arthur Brooke's The Tragical History of Romeus and Juliet.

If we want to link Mercutio's name to anything, it should be to Mercury, the Greek messenger god, and God of Trade.  If that's the case, what does he trade in?

Words.

And if to cement THAT concept, Shakespeare gives him one of the wildest speeches in the Canon, the Queen Mab speech...

[for that, my friends, you will have to wait until tomorrow...]