from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The absence or closure of a normal body orifice or tubular passage such as the anus, intestine, or external ear canal.
- n. The degeneration and resorption of one or more ovarian follicles before a state of maturity has been reached.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A condition in which a body orifice or passage in the body is abnormally closed or absent.
from the GNU version of the Collaborative International Dictionary of English
- n. Absence or closure of a natural passage or channel of the body; imperforation.
from The Century Dictionary and Cyclopedia
- n. The state or condition of being closed or imperforate; specifically, absence of a natural opening or passage: chiefly used in medicine and surgery.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an abnormal condition in which a normal opening or tube in the body (as the urethra) is closed or absent
New Latin atrēsia : Greek a-, not, without; see a-1 + Greek trēsis, perforation, orifice; see terə-1 in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)