Source : Webster's Revised Unabridged Dictionary (1913)

Crack-loo \Crack"-loo`\, n. Also Crackaloo \Crack"a*loo`\ .
   A kind of gambling game consisting in pitching coins to or
   towards the ceiling of a room so that they shall fall as near
   as possible to a certain crack in the floor. [Gamblers' Cant,
   U. S.]