The DICT Development Group

Search for:
Search type:

Database copyright information
Server information

2 definitions found
 for Egg cleavage
From The Collaborative International Dictionary of English v.0.48 :

  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
     [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]

From The Collaborative International Dictionary of English v.0.48 :

  Egg \Egg\ ([e^]g), n. [OE., fr. Icel. egg; akin to AS. [ae]g
     (whence OE. ey), Sw. [aum]gg, Dan. [ae]g, G. & D. ei, and
     prob. to OSlav. aje, jaje, L. ovum, Gr. 'w,o`n, Ir. ugh,
     Gael. ubh, and perh. to L. avis bird. Cf. Oval.]
     1. (Popularly) The oval or roundish body laid by domestic
        poultry and other birds, tortoises, etc. It consists of a
        yolk, usually surrounded by the "white" or albumen, and
        inclosed in a shell or strong membrane.
        [1913 Webster]
     2. (Biol.) A simple cell, from the development of which the
        young of animals are formed; ovum; germ cell.
        [1913 Webster]
     3. Anything resembling an egg in form.
        [1913 Webster]
     Note: Egg is used adjectively, or as the first part of
           self-explaining compounds; as, egg beater or
           egg-beater, egg case, egg ladle, egg-shaped, etc.
           [1913 Webster]
     Egg and anchor (Arch.), see egg-and-dart in the
        vocabulary, below; -- called also egg and dart, and egg
        and tongue. See Anchor, n., 5. --Ogilvie.
     Egg cleavage (Biol.), a process of cleavage or
        segmentation, by which the egg undergoes endogenous
        division with formation of a mass of nearly similar cells,
        from the growth and differentiation of which the new
        organism is ultimately formed. See Segmentation of the
        ovum, under Segmentation.
     Egg development (Biol.), the process of the development of
        an egg, by which the embryo is formed.
     Egg mite (Zo["o]l.), any mite which devours the eggs of
        insects, as Nothrus ovivorus, which destroys those of
        the canker worm.
     Egg parasite (Zo["o]l.), any small hymenopterous insect,
        which, in the larval stage, lives within the eggs of other
        insects. Many genera and species are known.
        [1913 Webster]

Contact=webmaster@dict.org Specification=RFC 2229