Social unit
A social unit was an individual or a group of people, like a family, acting as an unit in society.
In 2368, Lal defined home as a "Place of residence. Social unit formed by a family living together." (TNG: "The Offspring")
In 3189, when attempting to teach the dynamics of social interaction to Su'Kal, Michael Burnham began the lesson with introducing him to social units. During the lesson, she asked him what he knew about family. (DIS: "Su'Kal")