E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A Capulet; a fiery young noble. (Shakespeare: Romeo and Juliet.)
It is the name given to the cat in the story of Reynard the Fox. Hence Mercutio says, Tybalt, you rat-catcher, will you walk? (iii. 1); and again, when Tybalt asks, What wouldst thou have with me? Mercutio answers, Good king of cats! nothing but one of your nine lives (iii. 1).