n. pl. fe·tus·es
1. The unborn young of a viviparous vertebrate having a basic structural resemblance to the adult animal.
2. In humans, the unborn young from the end of the eighth week after conception to the moment of birth, as distinguished from the earlier embryo.
[Middle English, from Latin fētus, offspring; see dhē(i)- in the Appendix of Indo-European roots.]
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