blob of beige foundation. Foundation is a type of cosmetic preparation applied to the face. Often referred to as a 'base', a foundation is usually applied across the whole of the face except the eyes and lips. Its purpose it to make skintone and skin texture appear more even. Foundations can be used to cover up blemishes and other imperfections, and some are formulated to give a more youthful appearance by reducing the appearance of wrinkles.