previllous embryo

embryo /em·bryo/ (em´bre-o)

1. in animals, those derivatives of the zygote that eventually become the offspring, during their period of most rapid growth, i.e., from the time the long axis appears until all major structures are represented.

2. in humans, the developing organism from fertilization to the end of the eighth week. Cf. fetus.

3. in plants, the element of the seed that develops into a new individual.em´bryonalembryon´ic

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presomite embryo  the embryo at any stage before the appearance of the first somite.

previllous embryo  the embryo before the placental chorionic villi develop.

somite embryo  the embryo between the appearance of the first and the last somites.

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previllous embryo

[prēvil′əs]

Etymology: L, prae + villus, hairy; Gk, en, in, bryein, to grow

an embryo of a placental mammal at any stage before the development of the chorionic villi, which in humans occurs between the first and second months after fertilization.