"Pornography" is pretty vague, too. Even the U.S. Supreme Court has had difficulty coming up with a coherent definition for that.
Edit: to me (and I suspect most of us) pictures of women breastfeeding infants are not "pornography", but you still hear about such images being banned all the time.
Edit: to me (and I suspect most of us) pictures of women breastfeeding infants are not "pornography", but you still hear about such images being banned all the time.