Smartglasses are head worn electronics that have a small computer inside. They sometimes have a display and/or a speaker.
AR glasses are a type of smartglasses that have 3D tracking and 3D graphics display.
Most smartglasses, such as those made by Vuzix, are actually larger than a typical pair of glasses. Smartglasses may require innovations in electronics chip packaging to fit inside a small frame.
Smartglasses can be arbitrarily low compute power, and may have only the power of a microcontroller.
The electronics of smart glasses are inside the frame of the glasses, typically inside the stem(s).