A tween is a child between the ages of 8 and 12. The term "tween" is a blend of the words "teen" and "between" in the sense of "between childhood and adolescence". It is a neologism and marketing term for preteen. Sometimes the terms tweenie and tweenager are used to differentiate between older (10 to 15) and younger (7 to 11) age groups, respectively.

Tweens are in between childhood and adolescence, and they experience significant changes as they approach puberty. They are able to think in more abstract ways than they were before, having the ability to better intellectualize that the world doesn’t end with what’s right in front of them at that very moment. They become more aware of gender roles and expectations, and they start to worry about how they look and feel pressure to be sexy. They also start to move from being very close to parents to wanting to be more independent, but they still need a lot of help from their parents.

In summary, a tween is a child between the ages of 8 and 12 who is in between childhood and adolescence and experiences significant changes as they approach puberty.