Trade Ideas defines divergence as when there is change in market direction, such as when the price of an asset and an indicator, index, or similar asset move in opposite directions.  Divergence can be either positive or negative and both indicate major variations in the direction of the price.

Positive divergence takes place when a price makes a new low while the indicator moves upward.  Negative divergence occurs when the price makes a new high, but the indicator closes lower than the previous high.