Emily Dickinson Lexicon

PI-O-NEER, n. [Fr. pionnier, contracted from piochnier, from pioche, a pickax, piocher, to dig, that is, to peck, W. pigaw, Sp. and Port. picar. The Italians use guastatore, Sp. gastador, from guastare, gastar, to waste, to wear away. The Germans use schanzgräber, D. schansgraaver, a trench-digger.]

1. In the art and practice of war, one whose business is to march with or before an army, to repair the road or clear it of obstructions, work at intrenchments, or form mines for destroying an enemy's works. – Bacon.
2. One that goes before to remove obstructions or prepare the way for another.