Tween is a word coined independently with several meanings:

• Tween is a detergent polysorbate used to stabilize purified protein derivative (PPD) solution used in skin testing for tuberculosis exposure.
• J. R. R. Tolkien used it in The Fellowship of the Ring (published in 1954) to cover hobbit ages from twenty to thirty-two, too old to be teenagers but short of "coming of age" at 33.
• In popular culture around the start of the 21st century, it has been used for children just before their teens, "between" childhood and being teenagers. The word is used to evoke children in this stage of adolescence as a market for products generally associated with somewhat older role models like the Olsen twins.
• In animation, it is used to describe intermediate frames often added by an assistant animator or by computer. See tweening.
• Tween is also a web comic by Anthony Furtado. See Tween (webcomic).