Noun

1. A loud resonant repeating noise
2. A serious accident (usually involving one or more vehicles)
3. A sudden large decline of business or the prices of stocks (especially one that causes additional failures)
4. The act of colliding with something
5. (computer science) an event that causes a computer system to become inoperative

Verb

1. Fall or come down violently
2. Move with, or as if with, a crashing noise
3. Undergo damage or destruction on impact
4. Move violently as through a barrier
5. Break violently or noisily; smash
6. Occupy, usually uninvited
7. Make a sudden loud sound
8. Enter uninvited; informal
9. Cause to crash
10. Hurl or thrust violently
11. Undergo a sudden and severe downturn
12. Stop operating
13. Sleep in a convenient place