Philosophy (noun)

1. The study of the fundamental nature of knowledge, reality, and existence.
2. A particular set of beliefs or ideas about the nature of things.
3. A system of beliefs about human existence and the nature of the world.

Origin:

From middle english filosophie, from old french filosofie, from latin philosophia, from ancient greek φιλοσοφία (philosophía), from φιλεῖν (phileîn, "to love") + σοφία (sophía, "wisdo.m")

Examples:

1. He studied philosophy in college.
2. Her philosophy of life was to be kind to others.
3. The company's philosophy is to prioritize the well-being of their employees.