[Bo-ky ]. Prince of Purgatory. Purgatory is the “realm of Nosnot-Bocai.”
Sir, I last night received command To see you out of Fairy land, Into the realm of Nosnot-Bocai; But let not fear or sulphur choak-ye, For he's a fiend of sense and wit.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894