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]