Abortion is definitely a form of killing, but it is not murder. Not every form of killing qualifies as murder (for instance, soldiers killed in combat are not considered to have been murdered). An aborted fetus could not live on its own outside the uterus; it therefore has not every been fully alive and cannot be murdered.
Murder is the killing of a breathing human being who is capable of independent existence. Abortion is the termination of a fetus that is solely dependent upon the mother that is carrying for air and nutrition. Without the attachment to the mother through the umbilical cord, it could not survive independently. The ability to breathe independently is the different murder and abortion.
Although some individuals, and religious organizations, equate abortion with murder, from a legal standpoint there is a difference between abortion and murder. In the United States, abortion is not murder because a fetus is not deemed to legally be a human being for the purposes of laws governing the unlawful taken of a human life.
Think about it. You are literally shredding a child. In combat it is a noble and open thing done for something good. There is no good reason to do abortion. If you don't want the kid, give him up for adoption. If Albert Einstein's mother gave him up for adoption the world would have missed is brilliant theories. There is still potential in babies.