10oz/inch means, the servo can 'push' with a force of 10oz, one inch from the center of the servo-arm. (which means 5 oz 2 inch from the center of the arm, or 20oz 1/2 inch from the center of the arm)

Shameless copy-paste from another website:

The torque rating specifies how much force the servo can exert. It is typically expressed in units of ounce-inches (oz-in) or kilogram-centimeters (kg-cm). The higher the number, the more force the servo can exert. If you know the length of the servo arm that will be used, you can use this measurement and the servo torque rating to calculate how much force end of the arm can exert. A long arm will reduce the maximum possible force, and a short arm will increase it.