The American Orchid Society is a horticultural society for education, conservation, and research of orchids. It was founded in 1921, and has an international membership. It is a nonprofit 501 organization. It has been called an "industry group". As of 2001 it was the largest special interest horticultural organization in the world. The AOS is the parent organization for local orchid societies in North and South America. It is affiliated with 600 orchid societies worldwide.