I. ˌpī-ə-ˈnir noun
Etymology: Middle French pionier, from Old French peonier foot soldier, from peon foot soldier, from Medieval Latin pedon-, pedo — more at pawn
Date: 1523
1. : a member of a military unit usually of construction engineers
2.
a. : a person or group that originates or helps open up a new line of thought or activity or a new method or technical development
b. : one of the first to settle in a territory
3. : a plant or animal capable of establishing itself in a bare, barren, or open area and initiating an ecological cycle
II. verb
Date: 1780
intransitive verb
: to act as a pioneer
pioneer ed in the development of airplanes
transitive verb
1. : to open or prepare for others to follow ; also : settle
2. : to originate or take part in the development of
III. adjective
Date: 1836
1. : original , earliest
2. : relating to or being a pioneer ; especially : of, relating to, or characteristic of early settlers or their time