What are Muntins?

Definition of Muntins in Construction
Many times used interchangeable with grilles. A muntin is a spacer, horizontal or vertical, in a window or door unit that extends from a rail or stile or from one mutin to the other. Muntins are grilles, and in most situations, the same designation can be used interchangeably. The term muntin is not universally used throughout the country. It is a type of almost cultural descriptive term that in some areas of the country is understood immediately and in others, not at all.