vascular Pronunciation: ⁄ ˈvaskjʊlə ⁄ adjective Anatomy , Zoology , & Medicine · relating to, affecting, or consisting of a vessel or vessels, especially those which carry blood: vascular diseasethe vascular system · Botany relating to or denoting the plant tissues (xylem and phloem) which conduct water, sap, and nutrients in flowering plants, ferns, and their relatives.