When two or more roles/life domains are both highly inflexible and highly impermeable, they are highly segmented. (Desrochers)
“[I]ntegration is denoted by roles that are weakly differentiated (low contrast), are not tied to specific places and times (flexible boundary), and allow cross-role interruptions (permeable boundary)” (p. 479).Ashforth, Kreiner and Fugate (2000) state that “roles that are highly differentiated (high contrast), tied to specific settings and times (inflexible), and permit few cross-role interruptions (impermeable) are highly segmented” (p. 476). (Ashforth, Kreiner, & Fugate, 2000).
Nippert-Eng (1996) states that, when work and home ‘realms’ are highly segmented, “the mental boundary between realms is clear and impregnable, resolutely preserving the distinctive characteristics of each sphere. There is no classificatory ambiguity for the extreme segmentor: everything belongs to ‘home’ or ‘work,’ two mutually exclusive categories. With no conceptual overlap between realms and their contents, there is no physical or temporal overlap between them, either” (pp. 5-6). (Desrocher).

As defined by Desrochers. Ashforth, B. E., Kreiner, G. E., & Fugate, M. (2000). All in a day's work: Boundaries and micro role transitions. Academy of Management Review, 25(3), 472-491. As defined by Desrocher citing Nippert-Eng Nippert-Eng, C. (1996). Home and work. Chicago: University of Chicago Press.