1. in psychoanalytic theory, an unconscious process in which anxiety generated by psychological conflicts is transformed into physical symptoms. Traditionally, this process was presumed to be involved in conversion disorder, but current diagnostic criteria for the disorder do not make such an implication.

2. actual change in an individual’s beliefs, attitudes, or behaviors that occurs as a result of social influence. Unlike compliance, which is outward and temporary, conversion occurs when the targeted individual is personally convinced by a persuasive message or internalizes and accepts as his or her own the beliefs expressed by other group members. Also called private acceptance. See also conformity.

3. the movement of all members of a group to a single, mutually shared position, as when individuals who initially offer diverse opinions on a subject eventually come to share the same position. See group polarization.

4. the process by which a person comes to embrace a new religious faith (or, sometimes, a more intense version of his or her existing belief). For example, a nonbeliever who becomes Catholic has experienced a conversion, as has a member of a minority religion who adopts the beliefs of a more mainstream faith. In Protestant traditions, conversion is often seen as a sudden transformation in which a person apparently undergoes a dramatic change in his or her personality, values, and lifestyle. Compare deconversion. —convert vb.