Definition of "embryo" []

• An organism in its early stages of development, especially before it has reached a distinctively recognizable form. (noun)
• An organism at any time before full development, birth, or hatching. (noun)
• The fertilized egg of a vertebrate animal following cleavage. (noun)
• In humans, the prefetal product of conception from implantation through the eighth week of development. (noun)
• Botany The minute, rudimentary plant contained within a seed or an archegonium. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• ""(4) _Fundamentally the embryo of a higher animal form never resembles the adult of another animal form, but only its embryo_" (p. 224)."
• "Even the term embryo, which is officially correct, conjures images from the negative side, but really these are a ball of about 100 cells and they haven't become anything yet, and they've only been in the laboratory and frozen."
• "Some use the term embryo up to two or three months."