The double bottom looks like the letter "W". The twice touched low is considered a support level.
Most technical analysts believe that the advance off of the first bottom should be 10-20%. The second bottom should form within 3-4% of the previous low, and volume on the ensuing advance should increase.
Англо-русский строительный словарь. — М.: Русский Язык.С.Н.Корчемкина, С.К.Кашкина, С.В.Курбатова.1995.
двойное дно
2
междудонный