bloom1
  
  v.
   - produce flowers; be in flower.
 - be or become very healthy.
 - technical coat (a lens) with a special surface layer to reduce reflection.
 
n.
     - a flower, especially one cultivated for its beauty. 
▸the state or period of blooming:
 the apple trees were in bloom.
 - a youthful or healthy glow in a person's complexion.
 - a delicate powdery surface deposit on fruits, leaves, or stems.
 - a full, bright sound in a musical recording.
 - a rapid growth of microscopic algae or cyanobacteria in water resulting in a coloured scum on the surface.
 
 
  Etymology
  ME: from ON blóm ‘flower, blossom’, blómi ‘prosperity’, blómar ‘flowers’.
 
  
    
bloom2
  
  n.
 a mass of iron or steel hammered or rolled into a thick bar for further working. 
▸historical an unworked mass of puddled iron.
v.
 
[
usu. as noun blooming]
 make (metal) into such a mass.
 
  Etymology
  OE blōma, of unknown origin.