The Collaborative International Dictionary of English v.0.48:

Supercharge \Su`per*charge"\, v. t. [imp. & p. p.
   Supercharged; p. pr. & vb. n. Supercharging.] [Pref.
   super- + charge. Cf. Surcharge.] (Her.)
   To charge (a bearing) upon another bearing; as, to
   supercharge a rose upon a fess.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Supercharge \Su`per*charge"\, n. (Her.)
   A bearing charged upon another bearing. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

supercharge
    v 1: increase or raise; "boost the voltage in an electrical
         circuit" [syn: boost, advance, supercharge]
    2: increase the pressure on a gas or liquid [syn: supercharge,
       pressurize, pressurise]