Failure of some tissue or organ to develop

Wikipedia Word definitions in Wikipedia
Aplasia (from Greek a —not; plasis —molding) is defined in general as "defective development or congenital absence of an organ or tissue ." In the field of hematology , the term refers to "incomplete, retarded, or defective development, or cessation of ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Aplasia \A*pla"si*a\, n. [NL.; Gr. ? priv. + ? a molding.] (Med.) Incomplete or faulty development. (Med.) a defect, retardation, or cessation of the process of generation of blood cells.

Wiktionary Word definitions in Wiktionary
n. (context pathology English) A condition marked by the incomplete development, or absence, of an organ or tissue.

WordNet Word definitions in WordNet
n. failure of some tissue or organ to develop

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1885, medical Latin, from Greek a- , privative prefix (see a- (3)), + -plasia .