a person who is among those who first enter or settle a region, thus opening it for occupation and development by others.
2.
one who is first or among the earliest in any field of inquiry, enterprise, or progress: pioneers in cancer research.
3.
one of a group of foot soldiers detailed to make roads, dig intrenchments, etc., in advance of the main body.
4.
Ecology. an organism that successfully establishes itself in a barren area, thus starting an ecological cycle of life.
5.
(initial capital letter) Aerospace. one of a series of U.S. space probes that explored the solar system and transmitted scientific information to earth.
6.
(initial capital letter) (formerly) a member of a Communist organization in the Soviet Union for children ranging in age from 10 to 16. Compare Komsomol, Octobrist.
–verb (used without object)
7.
to act as a pioneer.
–verb (used with object)
8.
to be the first to open or prepare (a way, settlement, etc.).
9.
to take part in the beginnings of; initiate: to pioneer an aid program.
10.
to lead the way for (a group); guide.
–adjective
11.
being the earliest, original, first of a particular kind, etc.: a pioneer method of adult education.
12.
of, pertaining to, or characteristic of pioneers: pioneer justice.
13.
being a pioneer: a pioneer fur trader.
Origin: 1515–25; < MF pionier, OF peonier foot soldier. See peon, -eer
One who ventures into unknown or unclaimed territory to settle.
One who opens up new areas of thought, research, or development: a pioneer in aviation.
A soldier who performs construction and demolition work in the field to facilitate troop movements.
Ecology An animal or plant species that establishes itself in a previously barren environment.
adj.
Of, relating to, or characteristic of early settlers: the pioneer spirit.
Leading the way; trailblazing: a pioneer treatment for cancer.
v.
pi·o·neered, pi·o·neer·ing, pi·o·neers
v.
tr.
To open up (an area) or prepare (a way): rockets that pioneered outer space.
To settle (a region).
To initiate or participate in the development of: surgeons who pioneered organ transplants.
v.
intr. To act as a pioneer: pioneered in development of the laser.
[French pionnier, from Old French peonier, foot soldier, from peon, from Medieval Latin pedō, pedōn-, from Late Latin, one who has broad feet, from Latin pēs, ped-, foot; see ped- in Indo-European roots.]
[pahy-uh-neer] 
) Aerospace. one of a series of U.S. space probes that explored the solar system and transmitted scientific information to earth.