Though you might see the word squaw in an old book, it's considered offensive nowadays — it's an outdated term for a Native American woman or wife.
Squaw comes from the Algonquian word squa, meaning "woman." Anthropologists used to use this word in academic writing, and you might also come across it in 18th- and 19th-century novels. Because of its racist and sexist overtones, however, writers now avoid using the word squaw altogether. You’re better off using a neutral word such as "woman" or "wife."