**Onset** (n) — the beginning of something, especially something unpleasant or unwanted.
Here are some examples of using the word «onset»:
1. The onset of winter brought with it cold temperatures and snowfall.
2. She experienced the onset of symptoms such as fever and headache, indicating an infection.
3. The company faced an economic downturn, and the onset of the recession hit them hard.
4. The onset of menopause caused her to experience hot flashes and night sweats.
5. The onset of war resulted in displacement and loss of life.
6. He felt a sharp pain in his chest, which was the onset of a heart attack.
7. The onset of the pandemic led to lockdowns and social distancing measures.
8. The onset of darkness made it difficult to see the path ahead.
9. The onset of puberty brought about physical and emotional changes in teenagers.
10. The onset of industrialization led to pollution and environmental degradation.