The Collaborative International Dictionary of English v.0.48:

Pioneer \Pi`o*neer"\, v. t. & i. [imp. & p. p. Pioneered; p.
   pr. & vb. n. Pioneering.]
   1. To go before, and prepare or open a way for; to act as
      pioneer.
      [1913 Webster]

   2. to take part in the early development of; to break ground
      in; to invent or originate.
      [PJC]