Sector 10 was a region of space, a sector located somewhere in the galaxy's Alpha or Beta Quadrants.
History and specifics
In the year 2365, around stardate 42523.7, the Federation starship NCC-31054 explored deep space in sector 010 around the same time. (TNG episode: "The Measure of a Man")
Sector 10 was the location of a small moon where a large Borg cube was constructed. (TNG novel: Resistance)