Longman Dictionary of Contemporary English
Wiktionary
n. A cosmetic made from coloured talc, applied to the face.
WordNet
n. cosmetic powder for the face
Wikipedia
Face powder is a cosmetic powder applied to the face to set a foundation after application. It can also be reapplied throughout the day to minimize shininess caused by oily skin. There is translucent sheer powder, and there is pigmented powder. Certain types of pigmented facial powders are meant be worn alone with no base foundation. Powder tones the face and gives an even appearance. Besides toning the face, some powders with sunscreen can also reduce skin damage from sunlight and environmental stress. It comes packaged either as a compact or as loose powder. It can be applied with a sponge, brush, or powder puff. Uniform distribution over the face is achieved more easily when a loose powder is applied.
Because of the wide variation among human skin tones, there is a corresponding variety of colors of face powder. There are also several types of powder. A common powder used in beauty products is talc (or baby powder), which is absorbent and provides toning to the skin.
It can also be applied generously to the higher points of the face to brighten, colour correct and highlight, through a technique termed baking (aka cooking). this technique also helps to increase the coverage of the make-up whilst helping the makeup stay in place for longer.