The Collaborative International Dictionary of English v.0.48:
Aureola \Au*re"o*la\, Aureole \Au"re*ole\, n. [F. aur['e]ole,
fr. L. aureola, (fem adj.) of gold (sc. corona crown), dim.
of aureus. See Aureate, Oriole.]
1. (R. C. Theol.) A celestial crown or accidental glory added
to the bliss of heaven, as a reward to those (as virgins,
martyrs, preachers, etc.) who have overcome the world, the
flesh, and the devil.
2. The circle of rays, or halo of light, with which painters
surround the figure and represent the glory of Christ,
saints, and others held in special reverence.
Note: Limited to the head, it is strictly termed a nimbus;
when it envelops the whole body, an aureola.
3. A halo, actual or figurative.
The glorious aureole of light seen around the sun
during total eclipses. --Proctor.
The aureole of young womanhood. --O. W.
4. (Anat.) See Areola, 2.
5. the outermost region of the sun's atmosphere; visible from
earth during a solar eclipse, or in outer space by the use
of special instruments; a corona.
[WordNet 1.5 +PJC]