- any spontaneous expulsion of an embryo or a fetus before it is sufficiently developed to survive; miscarriage
- any deliberate procedure that removes, or induces the expulsion of, a dead embryo or fetus or a living embryo or fetus with the purpose of causing its death
- an aborted embryo or fetus
- anything immature and incomplete or unsuccessful, as a deformed creature, a badly developed plan, etc.
- arrest of development
- an organ whose development has been arrested
Origin of abortionClassical Latin abortio: see abort