Absence of the mammary glands (either through surgery or developmental defect)

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
medical Latin, from Greek amastos "without breasts," from privative prefix a- (see a- (3)) + mastos "breast" (see masto- ) + abstract noun ending -ia .

WordNet Word definitions in WordNet
n. absence of the mammary glands (either through surgery or developmental defect)

Wikipedia Word definitions in Wikipedia
Amastia refers to a condition where breast tissue, nipple, and areola is absent, either congenitally or iatrogenically. Amastia in girls can be treated with augmentation mammoplasty . Amastia differs from amazia (which involves only the absence of breast ...

Wiktionary Word definitions in Wiktionary
n. The absence of breast tissue, nipple, and areola.