an abnormality of the structure of a canal, duct, or body opening caused by a failure to develop properly or by an acquired closure, as with scar tissue
See atresia in American Heritage Dictionary 4
(ə-trēˈzhə, -zhē-ə)
noun
The absence or closure of a normal body orifice or tubular passage such as the anus, intestine, or external ear canal.
The degeneration and resorption of one or more ovarian follicles before a state of maturity has been reached.