Tilt Bar - The vertical bar used for adjusting the louver position.
Rabbet - A cut or groove along the edge of a stile between panels that allows them to form a joint to reduce light penetration.
High Quality Custom Made Interior Shutter Units
Most high quality shutters have rabbeted stiles to prevent light breaks between panels. This technique provide the best overall appearance for shutter units that have two or more panels. Quality shutter units attach panels to one another using a unique interpanel hinge between the panels.
Lower Quality Customized or Stock Shutters
Lesser quality shutters have long used square edge panels that do not prevent light breaks between panels. This is the least acceptable method of attaching shutter panels to one another. Most often hinges are mounted to the face or to the rear of the shutter panels resulting in an unattractive appearance. See picture.
A second technique developed by companies attempting to sell less expensive alternative shutters is to attach a tack strip to the face of one of the shutter panels to cover the gap between the panels.
Both of the above techniques are used by companies that usually customize their shutters to fit your window.