ex·plor·er \-ōrə(r), -ȯrə-\noun (-s) : one that explores: as a.: a person who travels or is sent in search of geographical or scientific information < an arctic explorer > b.: a youth of 14 years or over, who participates in an exploring program of the Boy Scouts of America — compare boy scout, cub scout c.: an instrument for exploring cavities especially in teeth : probe 1a