shiny refers to pokemon who are of a different color scheme then others, such as the red gyarados in the gold/silver/crystal versions, or Ash's noctowl in the series. with the exception of the aforementioned gyarados, shiny pokemon appear at 100% random and are impossible to hunt and, or search for. you have an equal chance to find a shiny in any blade of grass or drop of water just the same as any other. it is all luck.