'billyo' definitions:

Definition of 'billyo'

From: WordNet
noun
An unimaginably large amount; "British say `it rained like billyo' where Americans say `it rained like all get out'" [syn: billyo, billyoh, billy-ho, all get out]

Definition of 'billyo'

From: GCIDE
  • billyo \billyo\, billyoh \billyoh\n. a large amount; British say "it rained like billyo" where Americans say "it rained like the devil". [British]
  • Syn: billy-ho. [WordNet 1.5]