Lack of development. For example, agenesis of a toe means the toe failed to form.

Failure of formation of all or part of the sacrum (the lowest section of the spine). Currarino syndrome is a condition characterized by the combination of: Partial absence of the sacrum (the lowest portion of spine), Anorectal (anal and rectal) abnormalities, and An abnormal mass in front of the sacrum (due to a meningocoele or teratoma). The m [..]

absence or failure of formation of any part or organ.

the breakdown of a bodily component in regards to it's typical development.

(French : agénésie) Absence of an organ or structure.

(n) imperfect development; nondevelopment of a part

Birth Defect that results in a partial or complete absence of the Corpus Callosum. It may be isolated or a part of a Syndrome (e.g., Aicardi's Syndrome; Acrocallosal Syndrome; ANDERMANN Syndrome; [..]

An acquired or hereditary condition due to deficiency in the formation of Tooth Enamel (Amelogenesis). It is usually characterized by defective, thin, or malformed Dental Enamel. Risk Factors for Enam [..]

<embryology> A condition in which a part of the body (such as an organ or a tissue) does not completely develop or fails to develop at all. (09 Oct 1997)

Any imperfect development of the body, or any anomaly of organization.

absence.