i·so·sor·bide di·nit·rate (??s?-sôr?b?d? d?-n??tr?t?)n. A vasodilator drug, C6H8N2O8, used to treat and prevent angina pectoris.[iso- + sorb(itol) + -ide.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.