Pronunciation: (ik-splôr'ur, -splōr'-),[key] —n. 1. a person or thing that explores.
2. a person who investigates unknown regions: the great explorers of the Renaissance. 3. any instrument used in exploring or sounding a wound, a cavity in a tooth, or the like.
4. (cap.) Also called Explor'er Scout". a person between the ages 14 and 20 who is an active participant in the exploring program sponsored by the Boy Scouts of America.
5. (cap.) Aerospace.one of a long series of U.S. scientific satellites: Explorer 1 (1958) was the first U.S. artificial satellite.