A reading above zero means that Aroon-Up is greater than Aroon-Down, which implies that prices are making new highs more recently than new lows.
Conversely, readings below zero indicate that Aroon-Down is greater than Aroon-Up. This implies that prices are recording new lows more recently than new highs.
As you can see, the Aroon Oscillator is either going to be positive or negative the vast majority of the time. This makes interpretation straight-forward. Time and price favor an uptrend when the indicator is positive and a downtrend when the indicator is negative.
A positive or negative threshold can be used to define the strength of the trend. For example, a surge above +50 would reflect a strong upside move, while a plunge below -50 would indicate a strong downside move.
