[Word Family: noun: ↑break, ↑outbreak, ↑breakage; adjective: ↑breakable ≠ ↑unbreakable, ↑broken ≠ ↑unbroken; verb: ↑break]
if there is an outbreak of fighting or disease in an area, it suddenly starts to happen:
a cholera outbreak
outbreak of
outbreaks of fighting
the outbreak of World War II
⇨ break out at ↑break1