You still haven't defined "abortion" and leave it nebulous. I did:
Let us definitionally define "abortion":
"AN EXPLANATION OF MEDICAL TERMS USED IN THIS WORK, AND IN MEDICAL WORKS GENERALLY
... Abortion. A miscarriage, or producing a child before the natural time of birth. {1868 JNL, HBH 214.3} ..." - John Norton Loughborough, The Handbook of Health, page 214.3
Is a "miscarriage" a sin? (Depends on how it took place.) Is "producing a child before the natural time of birth" a sin? (did the child live? how did the event take place).
Therefore, in order for "abortion" to be "murder" the definition must be specific, and so here is a definition from Black's Law Dictionary:
"...
ABORTION
The artificial or spontaneous termination of a pregnancy before the embryo or foetus can survive on its own outside a woman’s uterus. ..." -
What is ABORTION? definition of ABORTION (Black's Law Dictionary)
"...
MURDER
The crime committed where a person of sound mind and discretion (that is, of sufficient age to form and execute a criminal design and not legally “insane”) kills any human creature in being (excluding quick but unborn children) and in the peace of the state or nation (including all persons except the military forces of the public enemy in time of war or battle) without any warrant, justification, or excuse in law. with malice aforethought, express or implied, that is, with a deliberate purpose or a design or determination distinctly formed in the mind before the commission of the act, provided that death results from the injury Inflicted within one year and a day after its infliction. See Kilpatrick v. Com., 31 Pa. 19S; Llotema v. U. S., 186 U. S. 413. 22 Sup. Ct 895, 46 L. Ed. 1225; Guiteau’s Case (D. C.) 10 Fed. 101; Clarke v. State. 117 Ala. 1, 23 South. 071, 67 Am. St. I top. 157; People v. Enoch, 13 Wend. (N. Y.) 167. 27 Am. Dec. 107; Kent v. People, 8 Colo. 5(13. 9 Pac. 852; Com. v. Webster, 5 Cush. (Mass.) 205. 52 Am. Dec. 711; Armstrong v. State. 30 Fla. 170. 11 South. 618. 17 L. R. A. 4S4; U. S. v. Lewis (C. C.) Ill Fed. 632; Nye v. People. 35 Mich. 16. For the distinction between murder and manslaughter and other forms of homicide, see HOMICIDE; MANSLAUGHTER. Common-law definitions. The willful killing of any subject whatever, with malice aforethought, whether the person slain shall be an Englishman or a foreigner. Hawk. P. C. b. 1, c. 13...." -
What is MURDER? definition of MURDER (Black's Law Dictionary)
So, legally and medically speaking, a woman who was injured in a fall (accidental) and so has an abortion (miscarry), is that murder? No.
So, to continue to ask, "Is abortion murder?" is so broad in scope (undefined) as to include both answers of 'yes' and 'no', depending on definition and situation. It is in effect a useless question (as far as attempting to determine the position of someone).