the onset of somethingBEGINNINGthe beginning of something, especially something bad 某事的开始[发作]〔尤指不好的事情〕 the onset of winter 冬天的来临
the onset of something• The loss of oestrogen at the onset of menopause may also be greater in smokers than nonsmokers.• This symptom usually occurs at the onset of sleep or upon waking.• It was the last upswing before the onset of slump, stagnation and mass unemployment.• It had gradually enlarged and began to leak some six weeks before his death and was heralded by the onset of headaches.• Doctors can slow the onset of the disease with drugs.• This was enough to slow the onset of their disease.• But cold weather and a scarcity of food on arable land usually brings numbers down with the onset of winter.• Yet the onset of daylight, with its much better conditions, brought the kiss of death.
→ the onset of something at onset(1)