“Stress and strain from one member of a dyad to the other.” (Hammer & Thompson citing Westman).
“[T]he transmission of the stress and strains of one spouse affecting the stress and strain of the other spouse.” (Hammer, Allen, & Grigsby, 1997).

As defined by Hammer & Thompson citing Westman in Work-Family Role Conflict a Conservation of Resources Theory, a Sloan Work-Family Encyclopedia Entry. Chestnut Hill, MA: Boston College. Retrieved from Westman, M. (2001). Stress and strain crossover. Human Relations, 54(6), 717-751. Hammer, L. B., Allen, E., & Grigsby, T. D. (1997). Work and family conflict in dual-earner couples: Within-individual and crossover effects of work and family. Journal of Vocational Behavior, 50, 185-203.