I think he means Aroon Oscillator....
DEFINITION of 'Aroon Oscillator'
What is the 'Aroon Indicator'
The Aroon indicator is a
technical indicatorused for identifying trends in an
underlying securityand the likelihood that the trends will reverse. It is made up of two lines: one line is called "Aroon up", which measures the strength of the uptrend, and the other line is called "Aroon down", which measures the
downtrend. The indicator reports the time it is taking for the price to reach, from a starting point, the highest and lowest points over a given time period, each reported as a percentage of total time.