em·bryo
ˈem-brē-ˌō 
plural embryos
1
a
: an animal in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems
especially
: the developing human individual from the time of implantation to the end of the eighth week after conception
b
archaic
: a vertebrate at any stage of development prior to birth or hatching
2
: the young sporophyte of a seed plant usually comprising a rudimentary plant with plumule, radicle, and cotyledons
3
a
: something as yet undeveloped
b
: a beginning or undeveloped state of something
… productions seen in embryo during their out-of-town tryout period …—
Henry Hewes
Henry Hewes
: embryo
embryogeny
Examples of embryo in a Sentence
Recent Examples on the Web
Rob Stein, NPR, 23 Dec. 2025
For the very first time, researchers captured incredible real-time, three-dimensional images and videos of a human embryo implanting into artificial uterine tissue.
—Lauren J. Young, Scientific American, 23 Dec. 2025
Just about all other aspects of a developing embryo, including its cellular and environmental components, have nothing to do with dad.
—Ivan Amato, Quanta Magazine, 22 Dec. 2025
Petrova's attorney, Gregory Romanovsky, told Fox News that his client was bringing back the embryos at the request of a professor at a French lab that was collaborating with Harvard.
—Rachel Wolf, FOXNews.com, 19 Dec. 2025
See All Example Sentences for embryo
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Noun
One of the most important moments in a human embryo's journey to becoming a baby is when the microscopic ball of cells burrows into the womb.
—Rob Stein, NPR, 23 Dec. 2025
For the very first time, researchers captured incredible real-time, three-dimensional images and videos of a human embryo implanting into artificial uterine tissue.
—Lauren J. Young, Scientific American, 23 Dec. 2025
Just about all other aspects of a developing embryo, including its cellular and environmental components, have nothing to do with dad.
—Ivan Amato, Quanta Magazine, 22 Dec. 2025
Petrova's attorney, Gregory Romanovsky, told Fox News that his client was bringing back the embryos at the request of a professor at a French lab that was collaborating with Harvard.
—Rachel Wolf, FOXNews.com, 19 Dec. 2025
See All Example Sentences for embryo
Cite this Entry
“Embryo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/embryo. Accessed 5 Jan. 2026.
Copy CitationKids Definition
embryo
noun
em·bryo
ˈem-brē-ˌō
plural embryos
1
: an animal in the early stages of development that are marked by cleavage, the laying down of the basic tissues, and the formation of primitive organs and organ systems compare fetus
2
: a tiny young plant within a seed
3
: a beginning or undeveloped stage
—used especially in the phrase in embryo
Medical Definition
embryo
noun
em·bryo
ˈem-brē-ˌō
plural embryos
1
archaic
: a vertebrate at any stage of development prior to birth or hatching
2
: an animal in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems
especially
: the developing human individual from the time of implantation to the end of the eighth week after conception compare fetus
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