A stenosis (/stəˈnoʊsəs/; plural: stenoses, /stəˈnoʊˌsiːs/) (from Ancient Greek στένωσις, "narrowing") is an abnormal narrowing in a blood vessel or other tubular organ or structure. It is also sometimes called a stricture (as in urethral stricture). The term coarctation is a synonym, but is commonly used only in the context of aortic coarctation.
Restenosis is the recurrence of stenosis after a procedure.