invagination

2 definitions found

invagination - Collaborative International Dictionary of English v.0.48 :

  Invagination \In*vag`i*na"tion\, n. [L. pref. in- + vagina
     sheath.]
     [1913 Webster]
     1. (Biol.) The condition of an invaginated organ or part.
        [1913 Webster]
  
     2. The inward movement of the wall of a tissue or cell, to
        form a cavity; also, the cavity thus formed.
        [PJC]
  
     3. Specifically: (Biol., Embryology) The inward movement of
        one part of the wall of a blastula, to form a gastrula;
        the process of gastrulation, in which layers of the ovum
        are differentiated.
        [1913 Webster +PJC]
  
     Note: In embolic invagination, one half of the blastosphere
           is pushed in towards the other half, producing an
           embryonic form known as a gastrula. -- In epibolic invagination
           , a phenomenon in the development of some
           invertebrate ova, the epiblast appears to grow over or
           around the hypoblast.
           [1913 Webster]

invagination - WordNet (r) 2.1 (2005) :

  invagination
      n 1: the condition of being folded inward or sheathed [syn:
           invagination, introversion]
      2: the folding in of an outer layer so as to form a pocket in
         the surface; "the invagination of the blastula" [syn:
         invagination, introversion, intussusception,
         infolding]