When writing historical novels, it's easy to let things slip into your writing that aren't era appropriate. I remember watching an episode of Paradise (a western), where a stuffed bear is referred to as a 'Teddy Bear'. Since teddy bears are named after President Theodore Roosevelt, no one would have called the toy by that name.
That scene has stuck in my mind for years and made me more aware of trying to get the language right in my stories. If you need help knowing if a word is appropriate, check out this site: Online Etymology Dictionary