A tattoo is a permanent design made on skin with a needle and ink. If you want a butterfly tattoo but you're scared of needles, you might settle for a temporary version.
The word tattoo is also a verb meaning stain the skin using needles and ink. It's probably a good idea to wait until you've been dating someone for more than a week before you tattoo their name on your arm. In music, a tattoo is continuous drumming, and a military tattoo is a drum or bugle that signals soldiers to return to their quarters at the end of the day.