Definition of TCK

"A TCK is an individual who, after having spent a significant part of the developmental years in a culture other than that of their parents,develops a sense of relationship to all of the cultures while not having full ownership in any. Elements from each culture are incorporated into the life experience, but the sense of belonging is in relationship to others of similar experience."

Third Culture Kids- The Experience of Growing Up Among Worlds
David C. Pollock and Ruth E. Van Reken