religion
This term carries a weight of institutionalization and tradition. It suggests a structured framework of beliefs, rituals, and moral codes that bind a group of people together. While spirituality is a personal, internal experience, religion typically implies an external, organized authority or a communal practice. In modern conversation, the word is often used loosely to describe an intense, almost blind devotion to a non-spiritual object or idea. For instance, a person might describe their loyalty to a specific sports team or a brand of technology as a religion, signaling a level of fervor that transcends rational preference.
Countable when referring to a specific organized faith like Buddhism or Islam. Uncountable when referring to the general concept of believing in a higher power or the act of being religious.