1. [n]  a piece of meat (or fish) that has been scored and broiled
2. [n]  an inferior dark diamond used in industry for drilling and polishing

CARBONADO is a 9 letter word that starts with C.

1. \Car`bo*na"do\, Carbonade \Car"bo*nade\, v. t. [imp. &
   p. p. {Carbonadoed}; p. pr. & vb. n. {Carbonadoing}.]
   1. To cut (meat) across for frying or broiling; to cut or
      slice and broil. [Obs.]
   
            A short-legged hen daintily carbonadoed. --Bean. &
                                                  Fl.
   
   2. To cut or hack, as in fighting. [Obs.]
   
            I'll so carbonado your shanks.        --Shak.
   
   

2. \Car`bo*na"do\, n.; pl. {Carbonadoes}. [Pg.,
   carbonated.] (Min.)
   A black variety of diamond, found in Brazil, and used for
   diamond drills. It occurs in irregular or rounded fragments,
   rarely distinctly crystallized, with a texture varying from
   compact to porous.