I think he means Aroon Oscillator....
DEFINITION of 'Aroon Oscillator'
What is the 'Aroon Indicator'
The Aroon indicator is atechnical indicatorused for identifying trends in anunderlying 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 thedowntrend. 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.
Don't know bout you guys, but if you look at Donchian channel nails trend changes better than Aroon up/down