-The Frame width is the distance between the inside of the temples, it is the amount of space there is for your head. Not the total width.
-The Frame Height includes the Lenses and the Frame.
-The Temple Length is measured starting from the lens to the end of the temple.
-The Bridge Width is the maximum amount of space there is for your nose about 2/3 of the way up, this measurement is more of an estimate because every nose is different and the amount of width available depends on the shape of your nose.
Helpful Tip: Start by measuring glasses that fit you well & use that as your reference. Most people can comfotably wear a range of sizes.