They learned to measure and count in better ways, and cracked the codes of physics, chemistry, and biology.
On the cracked veranda, her intensive care, the newest babies fail to thrive.
In a number of interviews over the years, Kelly admitted to Spoto that royalty was not all that it was cracked up to be.
mid-15c., past participle adjective from crack (v). Meaning "mentally unsound" is 17c. (cf. crack-brain "crazy fellow"). The equivalent Greek word was used in this sense by Aristophanes.
"split, opening," 14c., from crack (v.). Meaning "try, attempt" first attested 1836, probably a hunting metaphor, from slang sense of "fire a gun." Meaning "rock cocaine" is first attested 1985. The superstition that it is bad luck to step on sidewalk cracks has been traced to c.1890. Adjectival meaning in "top-notch, superior" is slang from 1793 (e.g. a crack shot).
Crazy; eccentric: You're cracked if you think I'll stay now (1692+)
[all senses are ultimately echoic; narcotics sense fr the sound of breaking crystals or the cracking sound the crystals make when smoked]