properly speaking, means a ewe whose teeth are worn out; but metaphorically it means any toothless old beldam. (Irish, criona, old; allied to the Greek geron, an old man.)
“Take up the bastard; take `t up, I say; give `t to thy crone.” —Shakespeare: Winter's Tale, ii. 3.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894