embryo

1 of 2

noun

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

embryo-

2 of 2

combining form

: embryo

embryogeny

Examples of embryo in a Sentence

Recent Examples on the Web

Noun

After Dobbs, however, activists intensified efforts to extend legal rights to embryos and fetuses. — Risa Cromer, The Conversation, 17 July 2026

So many people are having problems with getting pregnant, having a baby, getting eggs, making embryos. — Jayna Bardahl, New York Times, 15 July 2026

Because these cells are typically obtained from early-stage embryos donated through in vitro fertilization, their use has prompted debate over the moral status of human embryos. — Encyclopedia Britannica, 10 July 2026

Now, two new studies have used the technique to edit human embryos in the earliest stages of development, donated for research purposes by individuals who underwent IVF treatment. — Katie Hunt, CNN Money, 8 July 2026

Word History

Etymology

Noun

Middle English embrioun "embryo, fetus," borrowed from Medieval Latin embrion-, embrio, embryo, borrowed from Greek émbryon "newborn creature (in reference to a lamb), young, embryo or fetus," from em- em- + -bryon, derivative of bry-, stem of brýein "to swell with an abundance of growth, bloom, abound," of obscure origin

Note: In Medieval Latin the Greek neuter noun émbryon was reanalyzed as the base of Latin nasal stems (such as sermōn-, sermō "speech"), resulting in the nominative singular form embryo, which was borrowed into English. The stem embryon- was employed in New Latin derivatives, the sources of embryonal and embryonic. Compare bryo-.

Combining form

Late Latin, from Greek, from embryon

First Known Use

Noun

1548, in the meaning defined at sense 1b

Phrases Containing embryo

• embryo sac
• embryo transfer
• in embryo

Rhymes for embryo

• acknow
• aglow
• ago
• airglow
• aloe
• altho
• although
• ammo
• backflow
• backhoe
• banjo
• barbeau

Kids 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