The Collaborative International Dictionary of English v.0.48:

Star of David \Star" of Dav"id\
   A symbol consisting of two overlapped equilateral triangles
   forming a star with six points, used as a symbol of Judaism.
   It is also called Magen David, Mogen David, and Shield
   of David, and is shaped identically to the hexagram and
   Solomon's seal. It is used on the flag of the modern state
   of Israel.
   [PJC]

WordNet (r) 3.0 (2006):

Shield of David
    n 1: a six-pointed star formed from two equilateral triangles;
         an emblem symbolizing Judaism [syn: Star of David,
         Shield of David, Magen David, Mogen David, Solomon's
         seal]