A scar is a permanent mark on your skin that could be the result of an accident. You could also have a scar from having a doctor perform surgery on you. Scar can also be a verb and you can be scarred physically or emotionally.
Ex: When Laura burned her hand on the stove, the skin turned red. Later that day, the skin developed a sore that would leave a scar on her hand.
Ex: Dr. White told Susan that the incision to remove her appendix would scar her for life. He also told her that the operation was needed to save her life.
A scar can also result from an emotional wound. Some people claim to be scarred for life by an upsetting experience. Figuratively, the landscape can also be scarred. Some types of mining operations create large, open pits that are like scars on the earth.
Ex: When Diane's dog died last year, she cried for days. Her mother feared that Diane would be scarred for life by this upsetting experience.
A tattoo is a permanent mark on the skin, usually in the form of a design or a series of words. The tattoo artist uses needles to insert colored dyes under the skin. Tattoo is the action performed by the tattoo artist.
Ex: At one time, only sailors were known to have tattoos, and they generally got them in ports where their ships docked for a period of time.
Ex: Jenny wanted a very complicated tattoo on her arm, but the artist could only tattoo a part of it in one day. During the process, she tapped her fingers on the arm of the chair.
In music, a tattoo is a series of rhythmic taps on a drum. A tattoo is also a repetitive sound, for example the one a woodpecker makes, so a synonymous phrase would be tapping of a woodpecker.
Ex: I think Ringo Starr's ability to tattoo on the drums added interesting rhythms to the music of the Beatles.
Ex: When you hear the tapping of a woodpecker, you know that he is chipping away at a tree in search of food.