The use of familial terminology in religion has become more popular in schoarly discourse and in the Astronist philosophy of religion, its use has seen an increase as a way to simply convey complex philosophical ideas about the categorisation of and relationships between different religions. 

Here is a list of familial terminologies and their definitions in the context of the Astronist philosophy of religion:

• Mother religion - one that has birthed a multitude of denominations, is the religion that a denomination considers to be the founder of its lineage and that those denominations share the majority of the beliefs, practices and histories with the original religion with some differences to make the denomination distinct (e.g. Christianity in relation to Protestantism).
• Father religion - a religion that has denominations, but that those denominations outright reject the validity of the religion or philosophy which they have emerged (this marks the difference between a mother and father religion, but some religions may be classified as both at the same time) (e.g. Protestantism in relation to Catholicism).
• Brother/Sister religion - two religions which hold similar origins, share some similar beliefs and practices with shared histories (e.g. Buddhism and Jainism).
• Uncle/Aunt religion - two religions that are part of the same religious tradition, but that hold different origins, beliefs, practices, and different histories (e.g. Astronism and Astrology).
• Cousin religion - two religions that are classified as belonging to two different religious traditions, but that hold similar beliefs, and practices, or possibly similar origins (e.g. Sikhism in relation to Islam, or Judaism and Christianity in relation to Zoroastrianism).
• Nephew/niece religion - a denomination of an uncle/aunt religion (e.g. Astronism in relation to Chinese astrology as a denomination of Astrology).
• Grandchild religion - a denomination of a denomination of a religion (e.g. Methodism as a denomination of Protestantism which is itself a denomination of Christianity).
• Grandparent religion - a religion that birthed a denomination(s) before becoming extinct itself (e.g. Vedic religion in relation to Hinduism.