forty-niner

from WordNet (r) 3.0 (2006)

forty-niner
    n 1: a miner who took part in the California gold rush in 1849

from The Collaborative International Dictionary of English v.0.48

Forty-niner \For`ty-nin"er\, n.
   One the miners who took part in the California gold rush in
   1849; an argonaut. [Colloq., U. S.]
   [Webster 1913 Suppl.]