pioneer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One who ventures into unknown or unclaimed territory to settle.
• noun One who opens up new areas of thought, research, or development.
• noun A soldier who performs construction and demolition work in the field to facilitate troop movements.
• noun A species that is typically among the first to become established in a bare, open, or disturbed area.
• adjective Of, relating to, or characteristic of early settlers.
• adjective Leading the way; trailblazing.
• intransitive verb To venture into (an area) or prepare (a way).
• intransitive verb To settle (a region).
• intransitive verb To initiate or participate in the development of.
• intransitive verb To act as a pioneer.

from The Century Dictionary.

• To go before and open (a way); lead or prepare the way to or for.
• To act as pioneer; clear the way; remove obstructions.
• noun Milit.. one of a party or company of foot-soldiers who march before or with an army, and are furnished with digging- and cutting-implements, to clear the way of obstructions, repair the roads, dig intrenchments, etc.
• noun One who or that which goes before and opens and leads or prepares the way for others coming after; specifically, a first or early explorer or experimenter in any department of human enterprise.

from the GNU version of the Collaborative International Dictionary of English.

• verb To go before, and prepare or open a way for; to act as pioneer.
• verb to take part in the early development of; to break ground in; to invent or originate.
• noun (Mil.) A soldier detailed or employed to form roads, dig trenches, and make bridges, as an army advances.
• noun One who goes before, as into the wilderness, preparing the way for others to follow

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One who goes before, as into the wilderness, preparing the way for others to follow
• noun A person who is first or among the earliest in any field of inquiry, enterprise, or progress
• noun obsolete, military A soldier detailed or employed to form roads, dig trenches, and make bridges, as an army advances; a sapper.
• noun A member of any of several European organizations advocating abstinence from alcohol.
• noun communism A child of 10–16 years in the former Soviet Union, in the second of the three stages in becoming a member of the Communist Party.
• verb To go before and prepare or open a way for; to act as pioneer.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who helps to open up a new line of research or technology or art
• verb open up an area or prepare a way
• noun one the first colonists or settlers in a new territory
• verb take the lead or initiative in; participate in the development of
• verb open up and explore a new area