v.
     - (of a volcano) forcefully eject lava, rocks, ash, or gases.
 - break out suddenly:
 fierce fighting erupted.
 - 
(often erupt in)
 give vent to feelings in a sudden and noisy way:
 they erupted in fits of laughter.
 - (of a spot, rash, etc.) suddenly appear on the skin.
 - (of a tooth) break through the gums.
 
 
  Derivative
  
  Etymology
  C17: from L. erupt-, erumpere ‘break out’.