The organism in the early stages of growth and differentiation from fertilization to, in humans, the beginning of the third month of pregnancy. After that point in time, it is termed a fetus.
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1. An organism in the early stages of development. 2. In humans, the developing organism from conception until approximately the end of the second month; developmental stages from this time to birth are commonly designated as fetal. 3. A primordial plant within a seed. [G. embryon, fr. en, in, + bryo, to be full, swell]
- heterogametic e. a male e. with XY karyotype.
- hexacanth e. the e. of tapeworms of the subclass Cestoda, such as Taenia saginata, characterized by three pairs of hooks used for penetration through the gut of an intermediate host. SYN: oncosphere e..
- homogametic e. a female e. with XX karyotype.
- oncosphere e. SYN: hexacanth e..
- presomite e. an e. before the appearance of the first pair of somites, which are notable about 20–21 days after fertilization in humans.
- previllous e. the e. of a placental mammal prior to the formation of chorionic villi.

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em·bryo 'em-brē-.ō n, pl em·bry·os
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 esp the developing human individual from the time of implantation to the end of the eighth week after conception compare FETUS

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an animal at an early stage of development, before birth. In humans the term refers to the products of conception within the uterus up to the eighth week of development, during which time all the main organs are formed. Compare fetus.
embryonic adj.

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em·bryo (emґbre-o) [Gr. embryon] 1. in animals, those derivatives of the zygote that will eventually become the offspring, during their period of most rapid development, i.e., from the time the long axis appears until all major structures are represented. 2. in humans, the developing organism from fertilization to the end of the eighth week. Cf. fetus. 3. in plants, the element of the seed that develops into a new individual. embryonal, embryonic adj

Human embryo at various stages of development. The relative size has been distorted to emphasize correspondence of parts, and the ages are approximate.

Medical dictionary. 2011.


Look at other dictionaries:

  • EMBRYO — (Heb. עֻבָּר, ubbar), a child in the womb of its mother before its head emerges (Sanh. 72b; Sh. Ar., ḤM 425:2), the Hebrew ubbar meaning the unborn child in both the embryonic and fetal stages. Generally speaking, an embryo is incapable of having …   Encyclopedia of Judaism

  • Embryo — Saltar a navegación, búsqueda Embryo Información personal Origen Múnich, Baviera, Alemania Web Sitio web …   Wikipedia Español

  • Embryo — I. Entwickelung des Menschen. Embryo II. Entwickelung des Menschen …   Meyers Großes Konversations-Lexikon

  • Embryo — Sm im Entstehen befindlicher Organismus erw. fach. (15. Jh.) Entlehnung. Über l. embryo entlehnt aus gr. émbryon n. Neugeborenes, ungeborenes Leben , zu gr. brýein sprossen, treiben und l. en . Adjektiv: embryonal.    Ebenso nndl. embryo, ne.… …   Etymologisches Wörterbuch der deutschen sprache

  • Embryo — Chanson par Pink Floyd extrait de l’album Works Pays Royaume Uni Sortie 1er juin 1983 Durée 4:39 Genre …   Wikipédia en Français

  • Embryo — (griech., »Keim«; hierzu Tafel »Embryo: Die Entwickelung des Menschen I u. II«), in der Zoologie das junge Tier innerhalb des Eies oder Muttertiers, bei den Säugetieren auch Fötus (foetus, fetus, Frucht, Leibesfrucht) genannt. Die Entwickelung… …   Meyers Großes Konversations-Lexikon

  • embryo- — ♦ Élément, du gr. embruon « embryon ». embryo élément, du gr. embruon, embryon . ⇒EMBRYO , élément préf. Premier élément de compos., introduisant l idée d « embryon » et servant à former de nombreux termes du domaine médical : embryophore, subst …   Encyclopédie Universelle

  • Embryo — Em bry*o, n.; pl. {Embryos}. [F. embryon, Gr. e mbryon, perh. fr. ? in (akin to L. ? E. in) + ? to be full of, swell with; perh. akin to E. brew.] (Biol.) The first rudiments of an organism, whether animal or plant; as: (a) The young of an animal …   The Collaborative International Dictionary of English

  • Embryo — Em bry*o, a. Pertaining to an embryo; rudimentary; undeveloped; as, an embryo bud. [1913 Webster] …   The Collaborative International Dictionary of English

  • embryo — ► NOUN (pl. embryos) 1) an unborn or unhatched offspring in the process of development, especially an unborn human in the first eight weeks from conception. Compare with FETUS(Cf. ↑fetus). 2) the part of a seed which develops into a new plant. ●… …   English terms dictionary

  • embryo — [em′brē ō΄] n. pl. embryos [ME embrio < ML embryo < Gr embryon, embryo, fetus, thing newly born, neut. of embryos, growing in < en , in + bryein, to swell, be full] 1. an animal in the earliest stages of its development in the uterus or… …   English World dictionary

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