Gentoo was a term used in the 18th century, synonymous with "Hindu". For example, see The Gentoo Code.

Gentoo also refers to:

• the Gentoo Penguin
• the Gentoo Linux distribution, named after the Gentoo penguin
• the Gentoo file manager.

Tux, the Linux mascot, is not a Gentoo penguin, but in fact is a fictional character based on an Adelie penguin, or according to others, a Little Penguin.