Definitions

1. adjective

Lacking a patent opening, especially in the nose or Eustachian tube, or having a congenital absence of the external opening of the nasolacrimal duct.

“The infant was born with an atretic nose that required immediate medical attention.”

2. noun

A congenital or acquired abnormality in which a normal anatomical opening or structure is absent or reduced in size.

“The patient underwent surgery to correct her atretic ear canal.”