From Longman Dictionary of Contemporary Englishonseton‧set /ˈɒnset $ ˈɑːn-, ˈɒːn-/ ●○○ noun → the onset of somethingCOLLOCATIONSadjectivessuddenConsult the doctor if there is a very sudden onset of fever.abruptthe abrupt onset of the rainy season in India (=happening very quickly and suddenly)rapidSymptoms may include the rapid onset of nausea and vomiting.early/late onset (=happening earlier or later than commonly happens – used especially about serious illnesses)The patient had a family history of early onset Alzheimer's disease.verbsdelay the onset of somethingAn active and healthy lifestyle can delay the onset of disease in later life.mark the onset of somethingThe tradition originates from an old Celtic feast marking the onset of winter.
Examples from the Corpus
onset• Secondly the standard routes to chaos imply the existence of a well-defined onset of chaotic behaviour.• Was its onset sudden or gradual?• Mundo de siete pozos was composed in the relatively sunny days before the onset of cancer.• This was designed before the onset of destabilization, and aimed to restructure the formal school system.• The patients studied were seen and treated up to 3 hours from the onset of symptoms.• The curtains swung back to reveal Marie in a glistening silver robe and an expression suggesting the onset of migraine. 