If you are not familiar with the unit of measurement:
1 oz-in = 0.00706 Nm
if you are not familiar with torque:
1 Nm torque translates to 1N of force at a radial distance from the shaft of the motor of 1 m. As 1N gravitational force corresponds to an approx. 0.1kg weight, 1 Nm torque can lift* 0.1kg weight 1m away from the shaft, or 1 kg weight 0.1m away ...
The T indicates the number of teeth or ridges in the servo spline. You need to match the servo spline to any device splines or they won't mate.
:EDIT: Because it's a good link, and because I hate it when links to resources rot, I figured I'd duplicate the information here from the excellent Servo City:
Servos have an output shaft that ...