or Parhelion, in physiology, a mock sun, or meteor, in form of a very bright light, appearing on one side of the sun.

The parhelia are formed by the reflection of the sun's beams on a cloud properly posted. They usually accompany the corona, or luminous circles, and are placed in the same circumference and at the same height. Their colours resemble that of the rainbow; the red and yellow are on the side towards the sun, and the blue and violet on the other. There are coronae sometimes seen without parhelia, and vice versa.

Parhelia are double, triple, &c., and in 1629 a parhelion of five fuses was seen at Rome, and in 1666 another at Arles of six.

M. Mariotte accounts for parhelia from an infinity of little particles of ice floating in the air, that multiply the image of the sun by refraction or reflection; and by a geometrical calculus he has determined the precise figure of these little icicles, their situation in the air, and the size of the corona of circles which accompany the parhelia, and the colours wherewith they are painted.