Divergence in trading means exactly that. When something is moving in opposition and diverging rather than running in tandem or moving towards. So, many indicators can be used when looking for divergence.
I keep it simple with a 10-period RSI. When the price action makes a new high or low and the indicator does not, then this is divergence.
This usually signals a high probability that a reversal is coming soon. However please remember that like all other technical analysis methods, it not 100% accurate.
'Market and Human' Psychology perspectives with tips on how to avoid common mistakes by 

