You can choose from two answers. Short version: I'm a Third Culture Kid, or Global Nomad. [Canadian/Pakistani]
Here's the TL/DR version.
Born in Pakistan but raised partly in three countries, so I identify with none of them.
A Third Culture Kid (TCK) is a person who has spent a significant part of his or her developmental years outside the parents' culture. The TCK frequently builds relationships to all of the cultures, while not having full ownership in any. Although elements from each culture may be assimilated into the TCK's life experience, the sense of belonging is in relationship to others of similar background.
Kay Eakin adapted this term and described a TCK as "someone who, as a child, has spent a significant period of time in one or more culture(s) other than [their] own, thus integrating elements of those cultures and their own birth culture, into a third culture". Because culture by definition is something that must be shared with others, David C. Pollock's definition recognizes the reality of what Eakin is describing but takes it back to Useem's idea that, as with any culture, the "third culture" is a way of life shared with others. Others have used different expressions to describe this same population. Currently they include 3CK or trans-culture kid. Around 1985, Norma McCaig used the term Global Nomad essentially to define the same group because (1) she didn't like being called a kid when she was grown up and (2) she wanted to make clear for future research purposes that this experience happened because of a parent's career choice (which was the case with the TCKs in Useem's first study, although Useem didn't mention this), not refugees or immigrants. McCaig did not want the nuances particular to each type of experience to be lost. For this reason, Ruth Van Reken is now suggesting a more comprehensive term, Cross-Cultural Kid (CCK), for all types of cross-cultural childhoods.