1. Incomplete embryonic development of the body or any of its parts.
2. Imperfect or incomplete development.

An imperfect or incomplete development of the body or any of its parts: At the time of the child’s birth, the doctors advised Mr. and Mrs. Johnson that their daughter was born with atelia and that she would grow up with an incomplete development of her body, as in a condition of infantilism in which an older child or adult keeps infantile or childish characteristics.