Chiasma

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Chiasm \Chi"asm\ (k[imac]"[a^]z'm), Chiasma \Chi*as"ma\
     (k[-i]*[a^]z"m[.a]), n. [NL. chiasma, fr. Gr. chi`asma two
     lines placed crosswise, fr. ? to mark with a [chi].] (Anat.)
     A commissure; an intersection or crossing of two tracts;
     especially, the optic commissure, or crucial union of the
     optic nerves. -- {Chi*as"mal}, a..


     [1913 Webster] chiasmatic
     chiasmal

From WordNet (r) 2.0 [wn]:

  chiasma
       n : an intersection or crossing of two tracts in the form of the
           letter X [syn: {chiasm}, {decussation}]
       [also: {chiasmata} (pl)]