This is the most universal of Hindu symbols and its sound is used in meditation. In Hinduism, the word “Om” is the first syllable in any prayer. More specifically, Om is used to symbolize the universe and the ultimate reality.
Estragon seems to have a faulty memory, forgetting things that happened the previous day, or not remembering that they are waiting for Godot. Anything that is not currently happening is not important to him.