"the cold spring"
Solar and lunar letters:
In Arabic, some letters are said solar, and other lunar. Solar letters are doubled after 'al' and the L is not pronounced (ex. الشَّمس pronounced 'ash-shams'). Lunar letters are not doubled after 'al' and the L is pronounced (ex. القَمر pronounced 'al-qamar').
R ر is a solar letter, therefore اَلْرَّبيع is pronounced 'ar-rabi3'