"the crack of a whip" "he heard the cracking of the ice" "he can hear the snap of a twig"
the act of cracking something
the process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)
Adjective:
very good;
"he did a bully job" "a neat sports car" "had a great time at the party" "you look simply smashing"