A person who's personal "culture" is a fusion of two or more cultures to which s/he was exposed during childhood. Often abbreviated to TCK
Third Culture Kids are often multilingual, very accepting and understanding of other cultures and good at adapting to new environments.
Third Culture Kids are most commonly the children of members of the military, international businessmen or diplomats, though the term can also be applied to the children of immigrants.
Notable TCKs include:
Barack Obama (Anglo-American mother, Nigerian father; raised in Hawai'i and Indonesia)
Kim Jong-il (Korean parents; raised in USSR, North Korea and China)
Keanu Reeves (English mother, American father; raised in Lebanon, Australia, USA and Canada)
Pete Docherty (British parents; raised in Northern Ireland, Germany, Cyprus and England)
Third Culture Kid: "My parents are Japanese and I was raised in France, so my culture is a third culture, a fusion of the Japanese and French cultures!"