A form of communication define in systems theory, which consists of quantities, differences, and analogies. This communication has connotative meaning. Such communication consists not of words, but of the nonverbal, paraverbal, and contextual aspects of interaction. Family therapists refer to this when they identify the process (as opposed to the content) of a family therapy session.

As the compliment to pragmatics, this term refers to a sensitivity toward holism, complexity, and the larger patterns which connect family members. A family therapist views therapy as an art and focuses more on patterns and holism and less on techniques. It has been asserted that to be successful, therapists must work from this perspective as well as a pragmatic position.

This clinical pattern which describes a process of expelling family members early and forcefully from the family systems, particularly at the stage of adolescent separation. These family systems often lack attachment and cohesiveness, and the adolescent is compelled to try to find with one's peers the closeness she/he has failed to experience within their family.

An area of study from systems theory, originally defined by Norbert Weiner as the science of communication and control, which entered the family therapy field through the work of Bateson, Jackson, Haley, and Weakland. Bateson suggested, epistemologically, that one lives in an ecosystem world which functions like a gigantic mind. Other have operationalized this concept clinically by suggesting the description of a family system and interventions toward a system cannot be separated from the distinctions which are drawn be the observer who is describing and working with that system.

A pattern of typology which identifies a family system of diffuse internal boundaries and often closed external boundaries. These systems display a high degree of emotional resonance and reactivity between members who may be over-concerned and over-involved in each other's lives. Such systems may delay separation and individuation of its members.

A concept defined by Boszormenyi-Nagy, which identifies a relational "credit" that family members may accumulate as a result of consideration offered to a parent or partner. It is seen in the balancing of parent-child relationships, and can accumulate across generations.

A concept from systems theory which suggests that similar outcomes may result from different origins, in contrast to the traditional cause-and-effect explanation.

A concept from systems theory which defines the multiple possibilities of any event. This concept describes the principle that similar origins may result in different outcomes.

A concept developed by Murray Bowen, which describes a process by which the levels of personal differentiation of the parents are passed on to their children. In other words, the levels of emotional functioning of the parents determine the levels of emotional functioning of the children. The concept explains how a given child may become the symptom bearer for the family. This concept may also apply to the projection by the family of roles, values, and other attributes onto spouses or children.

A concept in family systems which describes overt and/or covert patterns of actions and behaviors that are invoked to denote shared traditions, events, and celebrations. Family therapists may develop or prescribe alternative rituals to provide a family with structured interactions which offer new patterns of behavior or that will replace dysfunctional interactions. These prescribed rituals may also be planned to provide healing around such events as divorce, reconciliation, a young adult leaving home, or geographical location.

A concept from systems theory that describes the process whereby changes in a system may leave unaltered the underlying organization of that system. For family therapists, a clinical family may be said to undergo first order change when it adapts or accommodates but does not cease it's symptomatic functions in response to a therapeutic intervention. Thus, the family may have been symptomatic in one way, but it now may be in another.

Terms, which evolved from object relations theory and the psychiatric symptoms or Borderline Personality Disorder, that describe for family therapists a process of emotional splitting which occurs within a family system whereby one family member is perceived as gratifying or good and another is perceived as misbehaving or bad.

A concept developed by Ivan Boszomenyi-Nagy, which describes a foundation of emotional commitments and obligations experienced by family members toward their families of origin. Two types of loyalties are defined: vertical loyalties are those embedded in one's early childhood roles and family of origin attachments; horizontal loyalties occur at marriage with the development of new attachments to an adult partner.

A concept from systems theory which describes the tendency of a system to evolve and to change its structure.

A concept from systems theory which describes the emergence of a system's organizational patterns which leads to knowledge about the system. This concept is the opposite of entropy.

These concepts from Family of Origin Therapy describe reciprocal roles within a family system. For example, an underfunctioning member may be dependent on a partner for caretaking or to assume responsibility for activities one is unable or unwilling to do. An overfunctioning member may feel emotionally responsible for the well-being of the partner and even act to compensate for real or imagined deficits in the functioning of the other. While this relationship may assist family functioning when levels of stress are low, increases in stress may push both members to polarized behaviors. A parent may assume and overfunctioning role which maintains a child at an excessively dependent and underfunctioning role.

The family systems dynamic by which members perceive and mark distinctions in their interactions with one another. Each partner believes that what she or he says was caused by what the other did or said.

A concept from systems theory that describes the process of change in a system which alters the fundamental organization of the system. In family therapy a symptomatic system can be said to undergo this change when a therapeutic intervention fundamentally disrupts the pattern of symptomatic interactions so that it ceases. The family's previous organization, which reinforced the symptomatic pattern, is replaced by a different organization.

A clinical intervention from Structural Family Therapy where the family therapist interferes with a dysfunctional transactional in the system by adding more emphasis or force to a certain behavior or role. The goal is to interfere with the equilibrium of the system which maintains the problem. A therapist might join with one family member in order to force other members to interact in a reciprocal or runaway manner.