Nimbus \NIM-buhs\ , noun;
1. (Fine Arts) Any circle, or disk, or any indication of radiant light around the heads of divinities, saints, and sovereigns, upon medals, pictures, etc.; a halo
2. A cloud or atmosphere (as of romance or glamour) that surrounds a person or thing
3. (Meteorology) A rain cloud
This word dates to the 1610's and originally meant "bright cloud surrounding a god" from Latin nimbus ("cloud"). It may be related to nebula, which means "cloud, mist". The meaning of "halo" is first attested in 1730 and the meteorological sense is from 1803. Later words like nimbostratus (1932) and cumulonimbus (1887) were coined for meteorological purposes.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Wednesday, February 23
Etymologies come from the Oxford English Dictionary and/or Etymonline.com