/koh'ahrk tay"sheuhn/ , n.
1. Pathol.
a. a narrowing of the lumen of a blood vessel.
b. a congenital anomaly of the heart in which there is a narrowing of the aorta, resulting in abnormal blood flow.
2. Entomol. the condition of having the body enclosed in a hardened shell or puparium.
[ 1400-50; late ME coartacioun pressure, constriction coar ( c ) tation-, s. of coar ( c ) tatio; see COARCTATE, -ION ]