NDI may refer to: Organisations National Dance Institute, a not for profit organization National Democratic Institute for International Affairs National Datacast Incorporated, the PBS datacasting subsidiary Science and technology Nephrogenic diabetes insipidus, a form of diabetes insipidus due primarily to pathology of the kidney Network Device Interface, an IP Video and Audio Protocol developed by NewTek Naphthalene diimides, dyes used in chemistry; See Naphthalene tetracarboxylic dianhydride New Dietary Ingredient, defined by the Dietary Supplement Health and Education Act of 1994 to be a dietary ingredient not marketed in the United States before October 15, 1994 Other uses Non-Destructive Inspection, in nondestructive testing Non-developmental item, in the Federal Acquisition Regulation Net disposable income