the process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)
the act of cracking something
a sudden sharp noise
"the crack of a whip"
"he heard the cracking of the ice"
"he can hear the snap of a twig"
"he did a bully job"
"a neat sports car"
"had a great time at the party"
"you look simply smashing"
- bang up - not bad - slap up