What are allusion in Siddhartha?

One example of an allusion in Siddhartha is the story of the Buddha, which is referenced multiple times throughout the novel. The character of Siddhartha himself also alludes to the historical figure of Siddhartha Gautama, who later became known as the Buddha. Additionally, the river in the novel can be seen as an allusion to the cycle of life and rebirth in Hindu and Buddhist philosophy.