A button is a typically thin, small disc of hard substance, attached to a piece of cloth by stitches sewn through holes in its centre. Buttons are made from bone, metal, plastic, wood, and other materials. Another frequently seen button is the "shank button." The front of the button has no visible holes, but from the back of the button protrudes a small shaft (the "shank") which has a hole going through it. A shank button may be sewn to cloth by means of this hole, rather than holes through the centre.
The most common use of buttons is to secure the openings of garments, by sliding the button through a slit in the piece of cloth to which the first is to be held. The slit is only sufficiently wide to allow the button to be fully pushed through while still remaining stitched to the first piece of cloth.
Buttons are also sometimes used for decorative effect, with or without a practical function. Because shank buttons do not have a visible hole, these are more easily decorated than buttons pictured here.