The stigma is the sticky knob at the top of the pistil. It is attached to the long, tubelike structure called the style. The style leads to the ovary that contains the female egg cells called ovules. The male parts are called stamens and usually surround the pistil.
In a flower, this landing zone and entrance is the stigma. It plays a pivotal role in reproduction. Most stigmas are adapted to trap pollen with hairs, flaps and other surfaces to increase their efficiency. Most stigmas are covered with a waxy, sticky substance.