1. [noun] An eruption, sudden appearance
2. [noun] A sudden increase.
3. [noun] An outburst or sudden eruption, especially of violence and mischief.
4. [noun] (uncountable) A geological layer that breaks out
5. [verb] (intransitive) To burst out
6. [verb] (intransitive) To break forth
7. [noun] A sudden violent spontaneous occurrence (usually of some undesirable condition); 'the outbreak of hostilities'.
