Here are some of Dorland’s Illustrated Medical Dictionary’s definitions of words pertaining to pregnancy and preborn children.
Embryo:
“The early or developing stage of any organism, especially the developing product of fertilization of the egg. In the human, the embryo is the developing individual from one week after conception to the end of the second month.”
Fetus:
“The unborn offspring of any viviparous animal; the developing young in the human uterus after the end of the second month.”
Zygote:
“1. The cell resulting from the fusion of two gametes; the fertilized ovum.
2. The individual developing from a cell formed by the union of two gametes.”
Gamete:
“Either of the two mature cells (ovum or sperm) which, when they unite, form a zygote which is a new individual.”
Dorland’s Illustrated Medical Dictionary (24th edition, 1965) 478 – 479, 547
This textbook was popular around the time of Roe V Wade. Pro-Life author William M Connolly wrote:
“Why didn’t the Supreme Court quote these definitions from Dorland’s work which made clear that from the moment of conception, a developing individual exists? The Supreme Court repeatedly quoted Dorland’s in Roe v. Wade.”
William M Connolly One Life: How the US Supreme Court Deliberately Distorted the History, Science and Law of Abortion (Xlibris, 2002) 401

