An in-oz (inch-ounce) is a torque force measurement. 16 inch ounces = 1 in-lb. 12 in-lb = 1 ft-lb (the common SAE torque measurement.) 192 in-oz = 1 ft-lb

You can get 1 inch-ounce torque by hanging 1 ounce of fishing weights on a 1 inch servo arm (that is parallel to the ground, with the output shaft parallel to the ground and 90 deg to the servo arm). 42 in-oz would be the same as either haning 42 oz off the end of a 1 inch arm, or 1 ounce off a 42 inch arm.

In physics, all forces have vectors, or directions they are acting on. In discucssing servos or tightening bolts in mechanics, Torque forces have a "rotational vector" acting to rotate some object about a given axis.