What is the meaning of Tween?

Alternative spelling of 'tween.

An action of tweening (inserting frames for continuity); a sequence of frames generated by tweening.

To generate intermediate frames in an animated sequence so as to give the appearance of smooth movement.

A child, especially a girl, in the age range between middle childhood and adolescence, normally between eight and thirteen years of age.

Of or having to do with tweenagers.

A number or age in the twenties (plural only), or a person of that age.

Source: wiktionary.org