The temple of eyeglasses is also called arm of eyeglasses. It is strip connect front frames and allow you wear it on your ear so as to fix your eyeglasses in front of your eyes. If you wear eyeglasses, you can see inside of your temple. Most of manufacturers will wrote the frame sizes on their eyeglasses frames (inside of temple). If you want measure the temple length, you shall measure it from one end to the other, including the bend part.
Temple length is the part of the glasses frame which rests on your ears. It is one of the three components of glasses size which is required to fit you properly when ordering glasses. If you want to measure the temple by yourself, you should try on the glasses to fnd one that fits you properly. Then take the glasses off and use a ruler to measure the temple. Before measurement, you should warm the temple so that it can be straightened completely. Then you can use your ruler to measure the entire length of the temple.