Thayer's Greek Lexicon

 1. light
  1) the light
1a1. emitted by a lamp
1a2. a heavenly light such as surrounds angels when they
appear on earth
  2) anything emitting light
1b1. a star
1b2. fire because it is light and sheds light
1b3. a lamp or torch
  3) light, i.e. brightness
1c1. of a lamp
2. metaph.
  1) God is light because light has the extremely delicate,
subtle, pure, brilliant quality
  2) of truth and its knowledge, together with the spiritual
purity associated with it
  3) that which is exposed to the view of all, openly, publicly
  4) reason, mind
2d1. the power of understanding esp. moral and spiritual truth

For Synonyms see entry G5817