onset

名词 onset:

1. the beginning or early stages
   同义词：oncoming
2. (military) an offensive against an enemy (using weapons)
   同义词：attack, onslaught, onrush

1. A rare congenital disorder of childhood that is characterized by rapid onset of the physical changes typical of old age, usually resulting in death before the age of20.
   (儿童的)早衰症一种少见的少年身体机能失调，以类似年老的身体快速变化为特征，其结果通常导致二十岁之前死亡
2. The attainment or onset of puberty.
   到达青春期或青春期开始
3. He met many difficulties at the first onset.
   在一开始时，他遇到了许多困难。

on.set

n.（名词）
An onslaught; an assault.
攻击：袭击
A beginning; a start:
开始：
例句：
the onset of a cold.
感冒初起