onset

US /ˈɑːn.set/
UK /ˈɑːn.set/
"onset" picture
1.

開始, 發作

the beginning of something, especially something unpleasant

:
The onset of winter brought cold weather.
冬季的開始帶來了寒冷的天氣。
Early onset of the disease makes it harder to treat.
疾病的早期發作使其更難治療。