In the garment industry, a placket refers both to a slit in clothing and to layers of fabric which may be used to conceal such a slit. While plackets can appear anywhere in clothing, the term is often used specifically to refer to the button down front of a jacket or blouse. Often, a garment's placket is described in promotional material such as a catalog, to give consumers an idea of what the garment looks like.

When a placket takes the form of a slit or opening, it may be designed to give the wearer access to a pocket, or it might be intended to facilitate putting on and removing clothing. In the latter case, the placket is often associated with fasteners which are intended to keep the placket closed while the garment is being worn. Snaps, buttons, zippers, and frogs can all be attached to plackets. Because there is often a great deal of stress at a garment opening, a placket is typically reinforced.

Garment reinforcement is very important because it ensures that a garment stays securely attached to the wearer and that it will not rip or tear. The closure of a garment is a particularly high stress area, since it is often pulled and twisted against the grain of the fabric. Typically, stiff interfacing is sewn inside a placket in this case to ensure that it will hold up to hard use while retaining its shape.

When a placket is used as a concealing flap, it may or may not be reinforced. In this instance, the placket is usually designed to cover fasteners and attachments underneath, creating a smooth and uninterrupted look in the garment. Often, this is called a “flat front placket,” because it evens out the visual appearance of the front of a garment. This type of placket is usually sewn from the same material as the garment, so that it will blend in.

For people who are curious about word origins, “placket” comes from the Old French plaquer, which means “to lay on,” and it is not related to “plaque,” although the two words do sound similar. A placket is always installed at the time of sewing, as it is an integral part of a garment. While it is possible to add a concealing flap to a garment later, it is difficult to make the new placket blend seamlessly with the garment, which defeats the point of a placket from the point of view of many designers.