The New Dictionary of Cultural Literacy, Third Edition. 2002.
skin
The external tissue that covers the body. As the bodys largest organ (it makes up about one twenty-fifth of an adults weight), the skin serves as a waterproof covering that helps keep out pathogens and protects against temperature extremes and sunlight. The skin also contains special nerve endings that respond to touch, pressure, heat, and cold. The skin has an outer layer, or epidermis, and a layer immediately below, called the dermis.