Segmentation Seg`men*ta"tion, n. The act or process of dividing into segments; specifically (Biol.), a self-division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster]

{Segmentation cavity} (Biol.), the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In the gastrula stage, the segmentation cavity in which the mesoblast is formed lies between the entoblast and ectoblast. See Illust. of {Invagination}.

{Segmentation nucleus} (Biol.), the body formed by fusion of the male and female pronucleus in an impregnated ovum. See the Note under {Pronucleus}.

{Segmentation of the ovum}, or {Egg cleavage} (Biol.), the process by which the embryos of all the higher plants and animals are derived from the germ cell. In the simplest case, that of small ova destitute of food yolk, the ovum or egg divides into two similar halves or segments (blastomeres), each of these again divides into two, and so on, thus giving rise to a mass of cells (mulberry mass, or morula), all equal and similar, from the growth and development of which the future animal is to be formed. This constitutes {regular segmentation}. Quite frequently, however, the equality and regularity of cleavage is interfered with by the presence of food yolk, from which results unequal segmentation. See {Holoblastic}, {Meroblastic}, {Alecithal}, {Centrolecithal}, {Ectolecithal}, and {Ovum}.

{Segmentation sphere} (Biol.), the blastosphere, or morula. See {Morula}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • segmentation — [ sɛgmɑ̃tasjɔ̃ ] n. f. • 1847; de segment 1 ♦ Littér. Division en segments. ⇒ fractionnement, fragmentation. ♢ Inform. Découpage d un programme en segments. 2 ♦ Biol. Première phase de l ontogenèse, au cours de laquelle l œuf se morcelle. ⇒… …   Encyclopédie Universelle

  • Segmentation — may mean: *Market segmentation, in economics Biology *A morphogenesis process that divides a metazoan body into a series of semi repetitive segments *Segmentation (biology), the structure that results from said processComputing *Segmentation… …   Wikipedia

  • Segmentation — Segmentation, Furchung, s. Entwickelungsgeschichte, S. 844 …   Meyers Großes Konversations-Lexikon

  • segmentation — index disassociation, division (act of dividing), split Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • segmentation — (n.) 1851, from SEGMENT (Cf. segment) + ATION (Cf. ation) …   Etymology dictionary

  • segmentation — [seg΄men tā′shən, seg΄məntā′shən] n. 1. a dividing or being divided into segments 2. Biol. the progressive growth and cleavage of a single cell into many others to form a new organism …   English World dictionary

  • Segmentation — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Sur les autres projets Wikimedia : « Segmentation », sur le Wiktionnaire (dictionnaire universel) De manière générale, le mot segmentation… …   Wikipédia en Français

  • segmentation — segment seg‧ment 2 [segˈment] verb [transitive] MARKETING to divide a large group of people into smaller groups of people of a similar age or with similar incomes, interests etc, so that products that are most suitable for each group can be sold… …   Financial and business terms

  • segmentation — /seg meuhn tay sheuhn/, n. 1. division into segments. 2. Biol. a. the subdivision of an organism or of an organ into more or less equivalent parts. b. cell division. [1850 55; SEGMENT + ATION] * * * ▪ zoology also called  metamerism, or metameric …   Universalium

  • segmentation — seg|men|ta|tion [ˌsegmenˈteıʃən, mən ] n [U] when something divides or is divided into smaller parts segmentation of ▪ the segmentation of society …   Dictionary of contemporary English

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