What does embryo mean?
An embryo is an organism at its earliest stage of development, before it has taken on the recognizable physical features of its species. In humans and many animals, this refers to the offspring growing inside the mother's womb following fertilization; in birds, reptiles, and plants, the term applies to the young contained within an egg or seed. The word carries strong scientific and medical associations, appearing frequently in discussions of pregnancy, genetics, stem cell research, and fertility treatment, where procedures such as embryo transfer are now commonplace. It can also be used figuratively to describe any idea or project still in its earliest, most undeveloped phase — one might say a business plan was 'still in embryo.' Derived forms such as 'embryonic' and 'embryology' extend the term into broader scientific vocabulary, making 'embryo' both a precise technical label and a flexible metaphor for beginnings.
nounAn unborn or unhatched offspring in the process of development, especially in the early stages before it reaches a form recognizable as a member of its species; in humans, roughly the first eight weeks after fertilization.
- A developing offspring in its early stages, particularly in humans and animals before the fetal stage (or before hatching in birds and reptiles).
- Figuratively: something at a rudimentary or incipient stage of development.
"The embryo develops rapidly during its first weeks of life."
"Doctors monitored the embryo carefully throughout the first trimester."
"The plan for the new library was still in embryo when funding was cut."
The standard plural simply adds '-s'; no irregular plural exists.
"Several embryos were successfully implanted during the procedure."
The word 'embryo' comes from Greek roots meaning 'to swell within' — literally describing something growing inside you before anyone could even see it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of embryo
The word 'embryo' entered English in the mid-sixteenth century via Latin and Middle French, ultimately deriving from the ancient Greek 'embrūon', meaning 'that which grows within.' The Greek compound joins 'en-', meaning 'in' or 'within,' with a root related to growth or swelling. Related scientific derivatives include 'embryology,' the study of embryos, and the adjective 'embryonic.'
Related word forms
How embryo is actually used
Primarily used in scientific, medical, and biological contexts; figurative use is somewhat formal and literary. The distinction between 'embryo' and 'fetus' matters in medical and legal writing.
Easily confused with embryo
In humans, an embryo is the developing offspring up to about eight weeks after fertilization, while a fetus is the later stage until birth.