501(c)(3) refers to the section of the Internal Revenue Code that defines which organizations are exempt from income tax as organizations with charitable, educational, or religious purposes (and a few other related purposes). These are the organizations that qualify to receive tax-deductible charitable contributions. There are other types of nonprofit organizations, such as trade associations, labor unions, social clubs, and social welfare organizations, but they generally cannot receive tax-deductible contributions or grants. Full voting members of the Mississippi Center for Nonprofits must be 501(c)(3) organizations.