Adaptability: The ability to react to the environment in a way that is favorable to the continued existence of a system.

Boundary: Something that fixes a limit, or the point or degree to which something extends. Family boundaries, which can be physical, psychological, or symbolic, are marked by rules and common understandings, such as who is “in” and who “out” of the family. Boundaries can be rigid, clear, flexible, or permeable.

Chronosystem: The time dimension of a system. This concept permits the measurement of change in social institutions and/or behaviors over historical time.

Cohesion: The degree to which family members spend time with each other, enjoy one another’s company, work well together, and care for one another.

Commitment: An agreement, promise, or pledge. It represents a willingness to give energy and resources to a particular person, group, or activity, and the behavior consistent with such a gift or agreement.

Communication: An exchange of information (facts, ideas, beliefs, attitudes, etc.) through speech, writing and non-verbal gestures.

Conjugal unit: A kinship group composed of husband, wife, and children.

Consensus: Group solidarity of sentiments and beliefs. It is a general agreement that exists among family members.

Exosystem: an environmental system with which individuals do not directly participate but nevertheless influences them. For example, a change in health care policy by an insurance company will affect all the families and individuals covered by that policy.

Extended family: The nuclear family plus other family members, such as in-laws, parents, siblings, cousins, nieces, nephews, etc.

Family of orientation: The family in which one is born or adopted into.

Family of procreation: The family one establishes through marriage or marriage promise.

Hierarchy: A set or series of places or positions ranked according to some standard. It is often associated with the distribution of power within a system.

Macrosystem: The cultural and sub-cultural components of a social system. The macrosystem includes values, ideologies, norms, laws, etc.

Mesosystem: The interaction that occurs between systems, such as the exchanges between family and school or family and workplace.

Microsystem: Environmental systems in which individuals participate directly, such as family, childcare, occupational settings, and so on.

Norm: A standard of behavior; a widely accepted and understood rule about how to behave.

Nuclear family: Two adult partners and their biological or adopted children.

Position: A place in a social hierarchy.

Poverty spell: A (short) period of time in which a family or individual lives in poverty.

Role: The expected behavior associated with a specific position.

Social class: A ranking or stratification system associated with the distribution of valued resources such as wealth, power, or prestige within a social structure.

Social institution: A stable set of positions, roles, rules, values, norms, statuses, and expectations that define a subset of behaviors associated with a specified unit of society, such as religion, politics, recreation, or education.

System: A configuration of parts that are in a dynamic relation of interdependency.

Value: A strong commitment to a highly esteemed or honored object or idea.