Final answer:
The term within Bowen's theory that refers to the expression of individuality while maintaining family connections is 'differentiation of self', which also measures the family's tolerance for difference.
Step-by-step explanation:
Within Bowen's theory, the term used to refer to the ability of family members to express their own individuality and act autonomously while remaining connected to others is differentiation of self. At the family level, this concept also indicates the degree to which difference is tolerated within the family system. Differentiation of self is crucial in understanding family dynamics and how families manage the balance between nurturing individual family members' autonomy and maintaining a connected and functioning family unit.