1. Ectopic pregnancy, ectopic pregnancy: the development of a fertilized ovum outside the uterus, as in a fallopian tube.
2. Implantation and subsequent development of a fertilized ovum outside the cavity of the uterus.
3. Gestation elsewhere than in the uterus (as in a fallopian tube or in the peritoneal cavity); also called: ectopic gestation, extrauterine gestation, extrauterine pregnancy.