An abstract noun is a noun that refers to an idea, feeling, quality, or state, rather than a physical object or entity. Examples of abstract nouns include "love," "happiness," and "justice."
Pilgrimage, on the other hand, refers to a specific type of journey, usually undertaken for religious reasons. It is a concrete noun, as it refers to a physical activity that can be undertaken by people.
Therefore, pilgrimage is not an abstract noun.