from
The Collaborative International Dictionary of English v.0.48
Brown bill \Brown" bill`\ [Brown + bill cutting tool.]
A bill or halberd of the 16th and 17th centuries. See 4th
{Bill}.
[1913 Webster]
Many time, but for a sallet, my brainpan had been cleft
with a brown bill. --Shak.
[1913 Webster]
Note: The black, or as it is sometimes called, the brown
bill, was a kind of halberd, the cutting part hooked
like a woodman's bill, from the back of which projected
a spike, and another from the head. --Grose.
[1913 Webster]