Citation, DOI & article data
An embryo (plural: embryos) is the term given to the precursor of a fetus and in humans the embryonic period is usually considered to be between the first (1st) and the eighth (8th) week (eleventh week according to some reports) of development after fertilisation. The term "fetal pole" is sometimes used synonymously with the term embryo. Following this period, the term fetus is used.
History and etymology
The term embryo is derived from the Greek word ἔμβρυον literally meaning "that which grows".