The New Dictionary of Cultural Literacy, Third Edition. 2002.
root
In biology, the part of a plant that grows downward and holds the plant in place, absorbs water and minerals from the soil, and often stores food. The main root of a plant is called the primary root; others are called secondary roots. The hard tip is called the root cap, which protects the growing cells behind it. Root hairs increase the root’s absorbing surface.
