The Collaborative International Dictionary of English v.0.48:

Merk \Merk\, n.
   A mark; a sign. [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Merk \Merk\, n. [See Marc.]
   An old Scotch silver coin; a mark or marc. [Scot.]
   [1913 Webster]