aplasia

noun Pathology.

1. defective development or congenital absence of a limb, organ, or other body part.

noun

1. pathol congenital absence or abnormal development of an organ or part

n.

1. Congenital absence of an organ or tissue.
2. Incomplete, retarded, or defective development of an organ or tissue.
3. Cessation of the usual regenerative process in an organ or tissue.