Final answer:
An abnormal attachment of two surfaces or structures in biology is known as adhesion, which is not to be confused with the specific attachment of antibodies to antigens or particular conditions like craniosynostosis.
Step-by-step explanation:
An abnormal attachment of two surfaces or structures that are normally separate is called adhesion. In the context of biology, adhesions typically refer to tissues within the body that stick together, which can sometimes lead to medical complications. For cells, an example of an adhesive structure is the anchoring junction, which mechanically attaches adjacent cells or to the basement membrane. Another example of an attachment is the process where antibodies connect to antigens, resulting in the formation of linked cell masses; however, this is not termed adhesion.
Also, in developmental biology, the premature closure of a suture line in the skull, called craniosynostosis, represents an abnormal fusion leading to growth deformities. Adhesion is a biological phenomenon that occurs in various contexts, such as in the attachment of cells to each other or the basement membrane. For example, anchoring junctions mechanically attach adjacent cells in tissues.