Contextual definition - defining Astronism within the context of a subject or in the context of a particular point of view.

• Sociologically
• Theological - Astronism is an Astronic panentheistic or non-theistic religion or philosophy emphasising an importance on The Cosmos as knowable causation rather than on the concept of God, an unknowable causation.
• Futurological - Astronism is an Astronic organised philosophy or religion prophesying that humanity’s destiny is based in spacefaring and that when spacefaring becomes available to the masses, a Great Departation will occur in which large portions of humanity will turn to a life of spacefaring.
• Soteriological - Astronism is an Astronic religion teaching that humanity‘s salvation or fulfilment will only be achieved through humanity’s destined exploration of The Cosmos, thus achieving a state known as transcension.
• Philosophically
• Eschatologically 
• Astronologically (focused on defining Astronism according to its main beliefs)
• Historically
• Biographically 

Theoretical / Academic definition - categorises Astronism and authoritatively lays down its theological and philosophical orientations .e.g. "Astronism is an Astronic cosmocentric organised philosophy".

Emotional definition - highlights some of the key elements of Astronism in ways that are perhaps more understandable to non-academics e.g. "Astronism is the love of stars" or "Astronism contemplates The Cosmos"