Noun

1. A sudden sharp noise
2. The act of cracking something
3. The process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)

Verb

1. Become fractured; break or crack on the surface only
2. Make a very sharp explosive sound
3. Make a sharp sound
4. Hit forcefully; deal a hard blow, making a cracking noise
5. Pass through (a barrier)
6. Break partially but keep its integrity
7. Break suddenly and abruptly, as under tension
8. Gain unauthorized access computers with malicious intentions
9. Suffer a nervous breakdown
10. Tell spontaneously
11. Cause to become cracked
12. Reduce (petroleum) to a simpler compound by cracking
13. Break into simpler molecules by means of heat