How do you spell Pioneer

Available Definitions:
1)  n. - A soldier detailed or employed to form roads, dig trenches, and make bridges, as an army advances.
2)  n. - One who goes before, as into the wilderness, preparing the way for others to follow; as, pioneers of civilization; pioneers of reform.
3)  v. t. & i. - To go before, and prepare or open a way for; to act as pioneer.