/
ˈmɪrɑːʒ, 
mɪˈrɑːʒ/
n.
  - an optical illusion caused by atmospheric conditions, especially the appearance of a sheet of water in a desert or on a hot road caused by the refraction of light from the sky by heated air.
 - an unrealistic hope or wish that cannot be achieved.
 
Etymology
C19: from Fr., from se mirer ‘be reflected’, from L. mirare ‘look at’.