Aphaeresis

Aphaeresis is a term in linguistics for the loss of the beginning sound or sounds of a word when another word is derived from it, such as the initial 'n' is lost from nadder meaning 'serpent', when another word adder which also means a serpent is derived from it. The initial n was lost in Middle English by wrong division of a naddre.

In medicine, aphaeresis is a name given to the removal of blood plasma from the body. The process involves withdrawal of blood from the body, separation of plasma and cells, and reintroduction of the cells. Aphaeresis is used in treatment of autoimmune diseases to remove antibodies from the blood.