"wall enclosing an outer court," 1300,
baylle, of unknown origin, perhaps ultimately connected to L.
bacula "sticks," on notion of "stakes, palisade fence."
Old Bailey, seat of Central Criminal Court in London, was so called because it stood within the ancient bailey of the city wall. The surname
Bailey usually is from O.Fr.
bailli, a later form of
baillif (q.v.).
[bey-lee] 
li